Additive manufacturing of composite materials

ABSTRACT

An additive manufacturing apparatus having a three-dimensional movement system comprising a first part; a second part coupled to the first part and movable relative to the first part; a third part coupled to the first part and the second part and movable relative to the first part and movable relative to the second part wherein the three-dimensional movement system moves an assembly in three dimensions relative to a base; a rotatable build table coupled to the base, and rotatable in a first plane parallel to the base; and a nozzle, wherein the assembly comprises the nozzle, wherein the nozzle is rotatable in a second plane not parallel to the base, wherein the nozzle comprises an opening for passing a printer filament through the nozzle, and for depositing the printer filament onto the build plate.

This application claims the benefit of U.S. Provisional Application No.62/306,072, filed Mar. 10, 2016, for ADDITIVE MANUFACTURING OF COMPOSITEMATERIALS which is incorporated in its entirety herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to additive manufacturingsystems and methods, and related systems and methods.

2. Discussion of the Related Art

Engineering and design of physical devices (e.g., mechanical devices orparts) has for decades required (often in order to validate or researchthe performance of designs under real loads, or in real environments) aprocess of prototyping the devices using available materials. Sometimesthese devices are assembled from smaller parts fastened, adhered,welded, or bonded together, and sometimes these devices were hewn fromraw materials that are worked, molded, cast, cut or machined.

As advances in technology have progressed, so too have technologies usedto prototype these designs become more numerous, and capable, and haveallowed for the more rapid prototyping of such devices, and even forfinal production of designs requiring limited numbers of units. Whereonce small batches of handmade parts needed to be worked, molded, cast,cut or machined, often by hand, highly automated computer systems arenow able to machine parts by milling parts from raw blocks of materialin a rapid and efficient manner, allowing the design process to progressthrough many design iterations in order to produce parts that aretested, redesigned, and then new parts made based on the redesign. Thisprocess is repeated until designs are sufficiently optimized andfinalized, for mass production.

Computer Numerical Control (CNC) milling machines are computercontrolled vertical mills with the ability to move a spindle (relativeto a workpiece) vertically along a Z-axis, and horizontally in anXY-plane in order to remove material in a programmed manner from a blockor raw material. This extra degree of freedom permits their use informing so-called 2.5-D surfaces such as relief sculptures. CNC andother such technologies, even those performed by hand, that removematerial from a block of raw material are referred to as subtractivemanufacturing techniques or machines.

Directed Energy Deposition (DED) covers a range of terminology: ‘Laserengineered net shaping, directed light fabrication, direct metaldeposition, three-dimensional laser cladding’. It is a more complexprinting process commonly used to repair or add additional material toexisting components (Gibson et al., 2010).

Directed Energy Deposition (DED) machines consist of a nozzle mounted ona multi-axis arm that deposits melted material onto a specified surface,where it solidifies.

The process is similar in principle to material extrusion, but thenozzle can move in multiple directions and is not fixed to a specificaxis. The material, which can be deposited from any angle using 5 axismachines, is melted upon deposition with a laser or electron beam. Theprocess can be used with polymers or ceramics but is typically used withmetals, in the form of either powder or wire.

Stereolithography (SLA or SL) is a form of 3-D printing technology usedfor creating models, prototypes, patterns, and production parts in alayer by layer fashion using photopolymerization, a process by whichlight causes chains of molecules to link together, forming polymers.These polymers then make up the body of a three-dimensional solid.

Stereolithography is an additive manufacturing process that works byfocusing an ultraviolet (UV) laser on to a vat of photopolymer resin.With the help of computer aided design software (CAD), the UV laser isused to draw a pre-programmed design or shape on to the surface of aliquid photopolymer in a vat. Because photopolymers are photosensitiveunder ultraviolet light, the resin is solidified and forms a singlelayer of the desired three-dimensional object. This process is repeatedfor each layer of the design until the three-dimensional object iscomplete.

In some applications, an elevator platform descends a distance equal tothe thickness of a single layer of the design into the photopolymer vat.Then, a resin-filled blade sweeps across a cross section of the layer,re-coating it with fresh material. The subsequent layer is traced,joining the previous layer. A complete three-dimensional object can beformed using this process.

More recently, 3-D printing technology has enabled designers to produceparts directly using materials deposited on stacked planes using apen-like nozzle to extrude liquefied material in patterns.Three-dimensional printing, also known as additive manufacturing (AM),refers to processes used to synthesize a three-dimensional object inwhich successive layers of material are formed under computer control tocreate an object. Objects can be of almost any shape or geometry and areproduced using digital model data from a three-dimensional model oranother electronic data source such as an Additive Manufacturing File(AMF) file or an (STereoLithography) STL file.

One example of digital model data is G-code. G-code (also RS-274), whichhas many variants, is the common name for the most widely used numericalcontrol (NC) programming language.

Before printing a three-dimensional model from an STL file, it mustfirst be examined for errors. Most CAD applications produce errors inoutput STL files: holes, inverted or inconsistent face normals,self-intersections, noise shells or manifold errors. A step in the STLgeneration known as “repair” fixes such problems in the original model.

Once error checking is completed, the STL file needs to be processed bya piece of software called a “slicer,” which converts the model into aseries of thin layers and produces a G-code file containing instructionstailored to a specific type of three-dimensional printer. This G-codefile can then be printed with three-dimensional printing client software(which loads the G-code, and uses it to instruct the three-dimensionalprinter during the three-dimensional printing process).

Traditional techniques like injection molding can be less expensive formanufacturing polymer products in high quantities, but additivemanufacturing can be faster, more flexible and less expensive whenproducing relatively small quantities of parts. Three-dimensionalprinters give designers and concept development teams the ability toproduce parts and concept models using a desktop size printer.

Some three-dimensional printing apparatuses and methods melt or softenthe material to produce layers. In fused deposition modeling (FDM), themodel or part is produced by extruding small beads or streams ofmaterial which harden immediately to form layers. A printer filament ofthermoplastic, metal wire, or other material is fed into an extrusionnozzle head (three-dimensional printer extruder), which heats thematerial and turns the flow on and off. FDM is somewhat restricted inthe variation of shapes that may be fabricated. Another technique fusesparts of the layer and then moves upward in the working area, addinganother layer of granules and repeating the process until the piece hasbuilt up. This process uses the unfused media to support overhangs andthin walls in the part being produced, which reduces the need fortemporary auxiliary supports for the piece.

However, none of these additive manufacturing technologies permit thedesigner to engineer the internal mechanical characteristics of thedeposited material of the device in three dimensions, and similarly,they all pose a significant design constraint when subsequentlygenerated layers need to be placed over voids in lower layers or piecesneed to be created in these voids that are not supported byalready-deposited or formed layers, but that are to be connected toyet-to-be-deposited or formed layers “above.” No adequate solution tothese problems has yet emerged.

SUMMARY OF THE INVENTION

Several embodiments of the invention advantageously address the needsabove as well as other needs by providing an additive manufacturingapparatus and method, and related apparatuses and methods, for makingthree dimensional parts.

In one embodiment, the invention can be characterized as an additivemanufacturing apparatus comprising a three-dimensional movement systemcomprising a first part; a second part coupled to the first part andmovable relative to the first part; a third part coupled to the firstpart and the second part and movable relative to the first part andmovable relative to the second part wherein the three-dimensionalmovement system moves an assembly in three dimensions relative to abase; a rotatable build table coupled to the base, and rotatable in afirst plane parallel to the base; and a nozzle, wherein the assemblycomprises the nozzle, wherein the nozzle is rotatable in a second planenot parallel to the base, wherein the nozzle comprises an opening forpassing a printer filament through the nozzle, and for depositing theprinter filament onto the build plate.

In another embodiment, the invention can be characterized as a method ofadditive manufacturing comprising moving a nozzle relative to a base infive dimensions comprising moving the nozzle in three dimensions definedby an x-axis, a y-axis, and a z-axis, rotating the nozzle in a plane notparallel to the base; rotating a build plate in a plane parallel to thebase; depositing a printer filament from the nozzle onto the buildplate.

The above embodiments are both encompassed by the generic rules that thebuild plate and nozzle must be able to travel with respect to oneanother in at least 5 linearly independent spatial dimensions. There aremany other embodiments of motion of the nozzle and build plate whichsatisfy this requirement.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of severalembodiments of the present invention will be more apparent from thefollowing more particular description thereof, presented in conjunctionwith the following drawings.

FIG. 1 is a side view of a nozzle of a three-dimensional printer;

FIG. 2 is a side view of the nozzle as described in FIG. 1;

FIG. 3 is a system of coordinates, such as Cartesian coordinates, and aplane such as be used in describing the operation of thethree-dimensional printer of FIG. 1;

FIG. 4 is a perspective view of the nozzle of FIGS. 1 and 2, supportedby a system of rails;

FIG. 5 is a side view of the nozzle as described in FIGS. 1 and 2depositing a printer filament to form a part;

FIG. 6 is a side view of the nozzle of FIGS. 1 and 2 depositing aprinter filament to form a part, and further showing conflict between ashape of a nozzle assembly and the part;

FIG. 7 is a perspective of a system in accordance with one embodiment ofthe present invention including the nozzle of FIGS. 1 and 2;

FIG. 8 is a schematic view of a system in accordance with anotherembodiment of the present invention including the nozzle of FIGS. 1 and2;

FIG. 9 is a partial cross-sectional view of one variation of the nozzleof FIGS. 1 and 2 including a tip of the nozzle, a reinforced printerfilament, and a constriction;

FIG. 10 is a partial cross-sectional view of another variation of thenozzle of FIGS. 1 and 2 including the tip of the nozzle, and aconsolidated printer filament;

FIG. 10A is a perspective view of a nozzle rotational assembly inaccordance with one variation for use with the nozzle of FIGS. 1 and 2;

FIG. 10B is a cross-sectional view of a nozzle radiative chamber for usewith a variation of the nozzle of FIGS. 1 and 2;

FIG. 10C is cross-sectional view showing a liquid cooling chamber withinone variation of the nozzle of FIGS. 1 and 2;

FIG. 11 is a cross sectional view of a printer filament that is aconsolidated printer filament, such as may be produced by the nozzle ofFIG. 10;

FIG. 12 is a schematic view of a nozzle, such as the nozzle of FIGS. 1and 2, with a Cartesian set of coordinate axes;

FIG. 13 is a schematic view of an additive manufacturing apparatus ofone embodiment including the nozzle of FIGS. 1 and 2;

FIG. 14 is a perspective three-dimensional view of a complex surface;

FIG. 15 is a cross-sectional view of a nozzle depositing a printerfilament onto the complex surface of FIG. 14;

FIG. 16 is a perspective view of a nozzle depositing a printer filamentonto a build plate, such as may be employed in the additivemanufacturing apparatus of FIG. 13;

FIG. 16A is a perspective view showing an interface betweenspring-loaded contact and slip rings such as may be employed in thebuild plate of FIG. 16;

FIG. 16B is a cross-sectional view of the build plate of FIG. 16 and theinterface of FIG. 16A;

FIG. 17 is a perspective view of a nozzle, such as is shown in FIGS. 1and 2, depositing a printer filament on the build plate of FIG. 16, inorder to produce the complex surface of FIG. 14;

FIG. 18 is a perspective view of a representative volume of a continuousfiber reinforced polymer composite produced from the consolidated fiberfilaments of FIG. 10;

FIG. 19 is a perspective view of three representative volume elements ofa reinforced polymer filament produced from the reinforced fiberfilaments of FIG. 9;

FIG. 20 is a perspective view of printer filaments such as the printerfilaments of FIGS. 18 and 19, aligned along three coordinate axes;

FIG. 21 is a perspective view of a structure comprised of printerfilaments that could be either reinforced printer filaments of FIG. 9 orconsolidated printer filaments of FIG. 10;

FIG. 22 is a flow diagram of an additive manufacturing process of oneembodiment of the present invention;

FIG. 23 is a perspective view of a fixed wall, a mesh and a load thatare instructive to the parts made by the additive manufacturing processof FIG. 22;

FIG. 24 is a side view of a loading configuration with two fixed pointsand one load in accordance with an example that may arise from atopological optimization made by the additive manufacturing process ofFIG. 22;

FIG. 25 is an abstract representation of a structure that represents agradient property throughout the structure, such as may be made by theadditive manufacturing process of FIG. 22;

FIG. 26 is a schematic diagram of a device that transmits information ina primary visual mode and displayed on the device are a plurality ofattachment points, a plurality of vectors and a plurality of moments;

FIG. 27 is a block diagram of a variation of an optimization processthat can be employed in the additive manufacturing process of FIG. 22;

FIG. 28 is a flowchart of a process for selecting processing techniquesfor making a printer filament in accordance with variations of thepresent invention;

FIG. 29 is a flowchart of one variation of the additive manufacturingprocess of FIG. 22;

FIG. 30 is a perspective view of an assembly for producing a printerfilament suitable for use in the additive manufacturing process of FIG.22;

FIG. 31 is a perspective view of an apparatus for processing a printerfilament in accordance with one variation, such as the printer filamentfor use in the additive manufacturing process of FIG. 22;

FIG. 32 is a close up (magnified) view of a consolidated printerfilament, such as may be used as the printer filament for use in theadditive manufacturing process of FIG. 22;

FIG. 33 is a flowchart illustrating a variation of an additivemanufacturing process including forming a composite printer filamentsuch as may be used in the additive manufacturing process of FIG. 22;

FIG. 34 is a flowchart illustrating another variation of an additivemanufacturing process including forming a composite printer filamentsuch as may be used in the additive manufacturing process of FIG. 22;

FIG. 35 is a flowchart illustrating a further variation of an additivemanufacturing process including forming a composite printer filamentsuch as may be used in the additive manufacturing process of FIG. 22;

FIG. 36 is a schematic diagram of several polymeric molecules such asmay be in the polymer filament such as may be used in the additivemanufacturing process of FIG. 22;

FIG. 37 is a cross sectional schematic diagram of an apparatus forprocessing a printer filament in accordance with another variation, suchas the printer filament for use in the additive manufacturing process ofFIG. 22;

FIG. 38 is a schematic diagram of an apparatus for processing a printerfilament in accordance with a further variation, such as the printerfilament for use in the additive manufacturing process of FIG. 22;

FIG. 39 is a cross sectional schematic diagram of an apparatus forprocessing a printer filament in accordance with an additionalvariation, such as the printer filament for use in the additivemanufacturing process of FIG. 22;

FIG. 40 is a cross sectional schematic diagram of an apparatus forprocessing a printer filament in accordance with another furthervariation, such as the printer filament for use in the additivemanufacturing process of FIG. 22;

FIG. 41 is a perspective view of a matrix block, and reinforcementfibers such as may be formed in a multiple matrix composite such as maybe formed in the printer filament utilized in accordance with a furtheradditional variation of the additive manufacturing process of FIG. 22;

FIG. 42 is a flowchart illustrating an additive manufacturing process inaccordance with another embodiment of the additive manufacturing processof FIG. 22;

FIG. 43 [c1] is a side cross-sectional view showing a coating on carbonfilaments prior to consolidating into a continuous filament for use asthe printer filament in some variations of the additive manufacturingprocess of FIG. 22;

FIG. 44 [c2] is a schematic diagram showing a coating applied to aprinted polymer composite part, and filling hollow portions with foam,prior to pyrolization as an option to mitigate part deformation andsubsequent removal in accordance with a further embodiment of theadditive manufacturing process of FIG. 22; and

FIG. 45 [c3] is a schematic diagram showing infiltration of a pyrolizedpart with silicon and joining in accordance with yet another embodimentof the additive manufacturing process of FIG. 22.

Corresponding reference characters indicate corresponding componentsthroughout the several views of the drawings. Skilled artisans willappreciate that elements in the figures are illustrated for simplicityand clarity and have not necessarily been drawn to scale. For example,the dimensions of some of the elements in the figures may be exaggeratedrelative to other elements to help to improve understanding of variousembodiments of the present invention. Also, common but well-understoodelements that are useful or necessary in a commercially feasibleembodiment are often not depicted in order to facilitate a lessobstructed view of these various embodiments of the present invention.

DETAILED DESCRIPTION

The following description is not to be taken in a limiting sense, but ismade merely for the purpose of describing the general principles ofexemplary embodiments. The scope of the invention should be determinedwith reference to the claims.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention. Thus,appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment.

Furthermore, the described features, structures, or characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. In the following description, numerous specific details areprovided, such as examples of programming, software modules, userselections, network transactions, database queries, database structures,hardware modules, hardware circuits, hardware chips, etc., to provide athorough understanding of embodiments of the invention. One skilled inthe relevant art will recognize, however, that the invention can bepracticed without one or more of the specific details, or with othermethods, components, materials, and so forth. In other instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring aspects of the invention.

Referring first to FIG. 1, shown is a side view of a nozzle inaccordance with one embodiment of the present invention. Shown is thenozzle 10, a generalized container 12, a printer filament 14 and asurface 16.

Not shown are electronic components and mechanical components of thecontainer 12. Also not shown are components of the nozzle 10 such asmetallic fins. Not shown are motors that can be in the container 12 toassist in movement of materials within the container 12 and motors thancan be coupled to the container 12 for movement of the container 12.Also not shown is a resistive heating element, and, in accordance withone variation, a plurality of sensors that may include thermocouples,luminance sensors, resistance change thermometers, and other sensorswhich may be used to determine the incident energy on a surface.

The printer filament 14 is within the nozzle 10. The container 12encloses and supports the nozzle 10. The container 12 can containvarious elements such as a fan, gears, levers, and other mechanicalsystems. The nozzle 10 is coupled to and held in place by the container12, permitting fluid material to flow from the container into the nozzlewhere the fluid material is formed into the printer filament. The fluidmaterial can be, for example, at least in part thermoplastic. Thecontainer 12 is attached to a mechanical system (not shown) that can becomprised of, for example, rails 40 a, 40 b, 40 c, such as is shown inFIG. 4. The container 12 can also or alternatively be connected to arobotic arm 84 such as is shown in FIG. 8. The printer filament 14 ispositioned axially through the nozzle 10. The nozzle 10 is connected toan electronic control system (not shown). The heating element is acomponent of the nozzle 10. Cooling fans (not shown) are positioned onthe outside of the nozzle 10, or, alternatively, nearby. Sensors, whichmay include thermocouples, luminance sensors, resistance changethermometers, and other sensors which may be used to determine theincident energy on a surface, can be positioned within the container 12.

In operation, the container 12, by connection to a movement system ofrails 40 a, 40 b, 40 c, or an arm 130, which moves the container 12,moves the nozzle 10, which is coupled to the container 12, along acomputer-controlled path. The computer-controlled path can bemathematically derived by firmware given geometric instructions. Thecontainer 12 can contain a plurality of mechanical subsystems thatenable the efficient feeding of the printer filament 14 into the topentrance 18 of the nozzle 10. Electronic systems control a resistive orcombustion based heating element or a plurality of resistive orcombustion based heating elements, which bring the nozzle 10 to atemperature at which the printer filament 14 material has the mechanicalproperties that are sufficient for extrusion, feeding, or chemicalreaction among multiple filaments 14, as is necessary for the givenapplication. The nozzle 10 can be metal or another thermally conductivematerial, or thermally insulating material, or a combination of metals,thermally conductive or insulating materials or any combination thereof.The mechanical systems feeding the printer filament 14 to the nozzle 10allow a continuous and controlled feeding of the material from thenozzle 10. The nozzle 10, in heating the printer filament 14, allows theprinter filament 14 to pass through a hole, which can be, in accordancewith some variations, of narrower diameter than the unheated printerfilament 14. The electronic system, in conjunction with the sensors, cancontrol the temperature of the nozzle 10 throughproportional-integral-derivative (PID) or other control to ensureconsistent temperature. The electronic control system can also controlthe fan as a cooling system, if cooling is necessary.

Referring to FIG. 2, a side view is shown of a nozzle 10 in accordancewith one embodiment of the present invention. Shown is the container 12and nozzle 10 as described in FIG. 1. Also shown is a simple part 48,and a small section of the printer filament 14.

The nozzle 10 is within the container 12, which together form a nozzleassembly 20. The simple part 48 is below the nozzle assembly 20. Thesmall section or piece of the printer filament 14 extends from thenozzle 10 to the part 48.

The nozzle 10 is used to print the simple part 48, which, as shown inthe present variation, is a block-shaped part. The relation between thenozzle 10 and container 12 is as described for FIG. 1.

The printer filament 14 is laid down along parallel planes 32 toconstruct the part 48 in three dimensions. The structure and use ofthese parallel planes 32 are elaborated upon in the description of FIG.3.

Referring next to FIG. 3, a system of coordinates 30 is shown, such asCartesian coordinates, and a plane 32.

The plane 32 is oriented parallel to an XY plane defined in the systemof coordinates 30. (It should be noted that in general the label of anaxis, or definition of a coordinate system, does not alter the systemitself.

Any consistent coordinate system used to describe or control some realsystem will be precisely the same as any other. Therefore, relabelingthe axes of the system of coordinates, or using other systems ofcoordinates, other than Cartesian, including, but not limited to polaror spherical, is also contemplated within the scope of the presentembodiment.)

The plane 32 defines the path along which the nozzle 10, such as of thevariety shown in FIG. 1 and FIG. 2 move. The movement, for example, caninclude any combination of movements in the X and Y directions to formcurves within the plane 32, but quasi-continuous movements do not extendto the Z direction. The Z-axis is considered only when switching into anew a XY plane of movement that is a standard delta (in the Z direction)from the prior position in space, typically chosen to be approximatelyequal to the thickness of the printer filament 14 used or the thicknessof an extruded bead from the nozzle 10. Unless otherwise specified, thecoordinates 30 also will be the definitive coordinates used whendescribing other parts, with the Z-axis being the vertical axis, and theX and Y axes 120 horizontal. The orientation of the figures will be suchthat reference to X, Y, or Z axes 120 for other figures can beunderstood with respect to this coordinate system, but alternatecoordinate systems are also contemplated regardless of their equivalenceto any other coordinate system such as this one.

Referring next to FIG. 4, the nozzle 10 and container 12 (together thenozzle assembly 20), as described in FIG. 1 and FIG. 2, are shown. Shownare a plurality of horizontal rails 40 a, 40 b, a flat plate 42, and aplurality of vertical rails 40 c. Shown are directional arrows 46, and apart 48 with layers 50. Not shown is a heating system 74 (FIG. 16B) anda plurality of electro-mechanical components 80 (FIG. 16A).

The vertical rails 40 c are connected to the flat plate 42. The part 48is directly on top of the plate 42. The nozzle container assembly 20 isabove the part 48, and by extension, the flat plate 42 as well. Thenozzle container assembly 20 is connected to the horizontal rails 40that is shown in the horizontal axes 120, with the horizontal rails 40a, 40 b going through the container 12. The arrows 46 are shownrelationally to the flat plate 42. A heating system 74 is incorporatedinto the flat plate 42. The flat plate 42 and vertical rails 40 c canconnect to electro-mechanical components 80 or assemblies.

The vertical rails 40 c are used to move the flat plate 42 in discretesteps enabling aspects of the description in FIG. 3. The flat plate 42holds the part 48 and provides heating to prevent warping and residualstresses as the printer filament 14 cools and consolidates onto the part48. Furthermore, the time for complete cooling might be such that theflat plate 42 is beneficial for the parts of the printer filament 14 andpart 48 that are already consolidated. The vertical movement of the flatplate 42 along the horizontal rails 40 a, 40 b allows the nozzlecontainer assembly 20 to stay in a single plane without moving in theZ-axis. Movement in this XY plane occurs by the use of the horizontalrails 40 a, 40 b in conjunction with electro-mechanical system that maybe controlled by a control system.

The movement occurs in conjunction to the extrusion described in FIG. 1and FIG. 2 to facilitate printing a planar layer of material. After thediscrete downward movement of the flat plate 42, which holds the part48, along the Z-axis, the nozzle container assembly 20 may be movedalong some other path in the XY plane, such that the printer filament 14forms a layer on top of a prior layer. By induction, this process, ifproperly determined with full constraints and set to execute by acomputation system that controls the electro-mechanical systems herein,the part 48 in three-dimensions will be formed without the need forsmooth movement along the third axis, which in this case is the Z-axis.The part 48 shown is one which is constructed of well-connected layers50, but the astute reader will notice that any two parallel layers 50 inwhich the shape of one layer has a hole or cutout of the full planarspace available that differs from an adjacent layer by an amount greaterthan the thickness of the printer filament 14 will not bewell-supported. There exists an arbitrarily large number of planestructures by which this method fails and the attempt to lay printerfilament 14 along the plane results in the printer filament 14 fallingsince the printer filament 14 has no surface to which to adhere andcounter gravitational force acting on it.

Referring next to FIG. 5, a side view is shown of a nozzle containerassembly 20 of the type described in FIG. 2 and FIG. 1. Shown areparallel layers 50 of a part 48 of various lengths.

The layers 50 are adhered to each other and the tip 100 of the nozzle 10connects to the end of the last component of printer filament 14 at ahighest point 150.

The nozzle container assembly 20 prints the parts as described in FIG.4. The layers 50 are made to be increasingly shorter to form a slant inthe part 48, which creates a surface 148 outside of the XY plane. Thisis a demonstration of how one might produce more complex parts with amore complex surface 149 using the methods described in FIG. 4.

Referring next to FIG. 6, a side view is shown of a nozzle containerassembly 20. Shown is a part 48, and a piece of printer filament 14.

The nozzle container assembly 20 is connected to the part 48 via theprinter filament 14 as the printer filament is extruded, and istherefore connected to the part 48. The edge of the container 12 of thenozzle container assembly 20 is shown touching the surface 149 of thepart 48, and therefore unable to move unabated through the XY plane.

The nozzle container assembly 20 has printed the part 48 shown and iscontinuing to add layers 50 to this part 48, with movements thatfacilitate greater complexity as described in FIG. 5. However, becausethe container 12 of the nozzle container assembly 20 should not touchthe part 48 and thereby possibly damage the part 48, the complexity ofthe part 48 is limited by a nozzle 10 being rotationally fixed relativeto the XY-plane. In such an arrangement, the slope of a surface beingprinted on is limited by the size (width) of the nozzle containerassembly 20, which must come into contact with the part 48 at somesufficiently large slope. Furthermore, since the printer filament 14 isshown as outside the XY plane this piece of printer filament 14 couldonly have been laid down by the system described in FIG. 4 if somehow acontinuous Z-movement or rotational movement relative to the XY-plane inconjunction with XY movements is enabled. This shows that evencontinuous Z-movement, while potentially beneficial, still has seeminglysimple parts that cannot be printed with filaments aligned arbitrarily.Of course, the part 48 shown could be printed with solely parallellayers 50 of printer filament 14 without running into the problem of thecontainer 12 impinging on the part 48, as the nozzle 10 would staynormal to the printed layers. However, this approach severely limits thestrength characteristics of the part 48, which, depending on itsapplication may require printer filament 14 orientations outside of theXY plane, such as is shown. As used above, the term “strengthcharacteristics” is used as a catchall to describe beneficialproperties, which can include many other such mechanical properties,such as vibrational damping, interesting strain behavior such as moregeometrically complex versions of extension-twist coupling, stiffness,or toughness, as well as non-mechanical properties, such as thermalexpansion, or reactive metal infiltratability, all of which are relatedto printer filament 14 orientations within a part 48.

Referring next to FIG. 7, a perspective view is shown of a system inaccordance with one embodiment of the present invention including aplurality of bars 70, a plurality of connectors 38, and a plurality offasteners (not shown). Also shown are a plurality of rails 40 a, 40 b,40 c, a build plate 42, a plurality of enclosures (not shown), a nozzle10, and a plurality of electro-mechanical assemblies 80 that canindependently move along linear axes and rotate the build plate 42.Further shown is a cross brace 82, which is shown with several of theplurality of rails 40 b, 40 c going through it. Now shown are variousother electromechanical pieces and componentry elaborated upon herein.

A first rectangular set of four of the plurality of bars 35 d, 35 e, 35f, 35 g is rigidly fastened together at ends 36, 37, at ninety degrees(90°) relative to one another to form a rectangular structure. Therectangular structure makes up a planar base 39 of the system, which mayhave various dimensions, depending on application and design choices.One of the four bars 35 d that make up the plurality of bars 70 thatcomprise the planar base 39 is attached rigidly to two parallel uprightbars 35 b, 35 c of the plurality of bars that extend in a perpendiculardirection from the planar base 39. These two parallel upright bars 35 b,35 c are terminated by a perpendicular crossbar 35 a at their other end91, such that the two parallel upright bars 35 b, 35 c are fastened intheir parallel configuration. Attached to the planar base 39 is aplurality of parallel rails 40 c, placed parallel to the upright bars 35b, 35 c. Attached to the parallel rails 40 a is an electro-mechanicalsub-assembly 39, which supports the build plate 42 and allows for bothrotation of the build plate 42 and motion along the parallel rails 40 a.Attached to and running parallel to the upright bars 35 b, 35 c is aplurality of parallel rails 40 c. The parallel rails 40 c support andallow for the linear motion of an electro-mechanical sub-assembly 82(which also serves as a cross brace) which in turn supports and allowsfor the linear motion of an arm 80. The arm 80 is an electro-mechanicalsub-assembly that moves in a direction parallel to the planar base 39and perpendicular to bar 35 d. The electro-mechanical sub-assembly 80includes the nozzle 10, electro-mechanical components necessary to drivefilament through the nozzle 10, and electro-mechanical components thatallow the nozzle 10 to also rotate around an axis 51.

Shown is an embodiment of a 5-axis printer in accordance with onevariation of a multi-axial manufacturing device 151. The three sets ofrails 40 a, 40 b, 40 c enable movement of the nozzle 10 in the X, Y, andZ directions, while the build plate 42 and nozzle 10 both rotate in axes120 referred to herein as A and B, respectively. This set of axes issufficient for the nozzle 10 to reach a point in space above and aroundthe build. This machine is controlled by a custom language similar toG-code that defines coordinates and feed rates for the movement of thenozzle 10, while the electro-mechanical sub-systems facilitate thesemovements.

Therefore, in operation, the 5-axis printer is able to feed the printerfilament 14 along any arbitrary curve in 3-dimensional space, ratherthan being limited to planar layers 50. This allows many more designpossibilities with the generation of novel structures.

Using the custom language for the 5-axis printer, slicing software isable to consider any planes since the 5-axis printer can feed a printerfilament 14 from any angle.

In operation, the type of nozzle 10 on the machine determines thestructure of the printer filament 14 and several possible printerfilament 14 structures are described, including those that benefit fromthe 5 axes of this machine. This rail structure, in accordance with someembodiments, can achieve accelerations exceeding 750 mm/s², which isvery fast compared to robotic arms 84 capable of greater than 3 axismovement. This system also has the benefit of lower costs and increasedreliability compared to many typical robotic arms 84 due partially tothe high rigidity of this system. This rigidity comes in part from theutilization of linear axes rather than radial axes, as well as from theutilization of rotational axes on both the part and the additivemanufacturing head, i.e., the nozzle 10. Other embodiments havedifferent shaped build plates as well as other variations that can beseen as instances of the embodiment disclosed.

Referring next to FIG. 8, shown is a robotic arm 84 with a base 86, aplurality of rods 88 and joints 89 and a nozzle assembly 20.

The rods 88 and joints 89 connect to form a robotic arm 84 that includesa mechanically grounded base 86 at one end. The other end of the arm 84holds the nozzle assembly 20, composed primarily of a heated nozzle 10and an extrusion motor (not shown), which may alternately be mountedexternally. A plurality of electrical and mechanical components may beincluded in the nozzle assembly 20, including but not limited to radialjoints, and stepper, piezoelectric, or BLDC motors with shaft encoders.

In operation, this robotic arm 84 is another embodiment of the machinedescribed in FIG. 7. Since the number of axes on a robotic arm 84 can begreater than 5, the present embodiment is beneficial for the additivemanufacturing techniques described herein. A robotic arm 84 system isbeneficial in that it can be easier to implement using one of the manyrobotic arms known in the art for various purposes other than additivemanufacturing and could be retrofitted for additive manufacturing ratherthan being designed from the ground up. Some auxiliary systems, which inaccordance with some variations, consists of a computer usingpurpose-built or modified software to interface the arm to g-code orother machining command language instruction sets, in addition tovarious control electronics, motors, mechanical assemblies and softwareto control the elements of the machine which are not normallyincorporated into the arm assembly are used in operation to control themovement of the arm 84 and the feeding of the printer filament 14material.

Referring next to FIG. 9, a cross-sectional view is shown which includesthe tip 100 of the nozzle 10, a reinforced printer filament 398. Alsoshown are short reinforcements 90, and a polymer matrix 114. Not shownis a heating mechanism 92.

The reinforced printer filament 398 is a reinforced filament thatcomprises an additional material in a polymer matrix 114. The polymermatrix 114 is the material that is not the reinforcement and inaccordance with one variation of the present embodiment is a polymer.Reinforcement comprises additional material 90 that may be discontinuousfiber filaments or other structurally reinforcing material. Reinforcedfiber filament variations of the printer filament 14 are depicted assuch with short line segments representing fibers. However, thereinforcement can also be a short reinforcement material comprisingflakes or material of a more complex morphology. Short reinforcementsthat are not structural are also contemplated. For instance, carbonblack could be added to increase electrical conductivity. A wide varietyof materials exist that can be added to a polymer in a printer filament14 which may act as reinforcement, as selected based on each applicationof the present embodiment.

A printer filament that is reinforced 398 is similar to a printerfilament that is consolidated 112 in that both printer filaments are ina final form that can be the direct input into additive manufacturingmachines in accordance with the embodiments described herein. Manymethods are described for consolidated printer filaments 112 as well asreinforced printer filaments 398, and the use of all those methods withthe style of those two printer filament not mentioned (when only one ismentioned) is also contemplated. Furthermore, the concept of areinforced printer filament 398 and consolidated printer filament 112are described as if only two materials comprise the printer filament 14.However, hybrids of these printer filaments or various compositions ofprinter filaments that have more than two constituent materials are alsocontemplated.

The printer filament 398 passes through the downstream end of the nozzle10 at a constriction 100. Part of the printer filament 398 is showndownstream of the end 100 of the nozzle 10 and been laid on a surface 16after being extruded through the end of the nozzle 10 via theconstriction 100. The short reinforcements 90 are contained within theprinter filament 398. The heating mechanism 92 is contained within thenozzle 10.

In operation, the printer filament 398 is passed through theconstriction 100 in the nozzle 10 and laid onto the surface 16, with thenozzle 10 moved by a computer controlled machine (not shown). The shortreinforcements 90 are dispersed uniformly in the printer filament 398.

In accordance with one embodiment, the reinforced printer filament 398comprises fiber filaments 90 in a thermoplastic polymer. Fiber filaments90 are the individual filaments in a fiber tow 388 or roving. A fiber388 tow is a bundle of filaments 90 and is a common form for fiberfilaments. Fiber tows 388 can contain a wide range of numbers offilaments ranging from hundreds to tens of thousands. Fiber filaments 90can be any material, for example, carbon fibers, Kevlar fibers, extendedchain polyethylene fibers, glass fibers, carbon nanofibers, diamondnanothreads, carbon nanotubes, or combinations of any of these. Thincoatings on these or other printer filaments that would improve adhesionor other forms of bonding between layers to improve interlaminar shearstrength or other properties, as would be feasible with a coating thatcan be thermoplastic compatible, containing nano-reinforcements such ascarbon nanotubes is also contemplated.

Such a reinforced printer filament 398 can be heated to an appropriatetemperature to allow the deformation or flow of the reinforced printerfilament 398 through the constriction 100. This deformation and flow ofthe printer filament 398 through the constriction 100 aligns the shortreinforcements 90 with one another and parallel to the flow of theprinter filament 398 (reinforcement axis 34) through the constriction100, which previously might not have a high degree of alignment alongthe reinforcement axis 34.

If the short reinforcements 90 are spherical such as that from a powderwhere a primary axis along the length of each piece of shortreinforcement material does not exist, then the aforementioned conceptof alignment is no longer relevant. Alignment of short reinforcementshas the benefit of increasing the mechanical properties along theprimary reinforcement axis since the short reinforcements provide mostof their mechanical properties such as increased strength and stiffnessalong their axis. This beneficially allows a higher degree ofoptimization since the part 48 application and associated loading willbe known. Therefore, less material may be used in meeting the designconstraints, saving weight in the final part 48 and time in itsmanufacture. This increase in anisotropy also has the benefit of makingthe properties more predictable so optimization can occur at all sincethe existing models for composite parts often assume unidirectionallamina. This high degree of alignment can provide a near-unidirectionalstructure to allow a better understood representative volume 180 elementin structural optimization or generative design.

Referring next to FIG. 10, shown is a cross-sectional view of an end (orconstriction 100) of the nozzle 10 and the consolidated printer filament112. The term consolidated printer filament 112 used herein to refer toa printer filament that is suitable for the additive manufacturingmachines of the present embodiment. More specifically, consolidatedprinter filament 112 means a printer filament 14 that comprises a matrix114 reinforced by fiber filaments 111 that are continuous along thelength of a segment of the printer filament 14. Consolidated in thiscontext means that a cross-section comprises the matrix and fiberfilaments, ideally having no gaps, as shown in FIG. 11. Furtherelaboration can be found in reference to FIG. 32, which illustrates themorphology of a consolidated printer filament 112. Shown are fiber tows388. A heating element 92 exists, but is not shown.

The printer filament 112 is aligned with the center of the nozzle 10with a segment of the printer filament 112 extending from the nozzle 10,part 48 of which segment is laid perpendicular to the nozzle's 10 centeraxis 34. The printer filament 112 moves in a direction substantiallyparallel to the center axis 34 as it passes through the nozzle 14. Theprinter filament is substantially coaxial with the center axis 34 as itmoves through the nozzle 10. The fiber filaments are distributedthroughout the printer filament 112, preferably uniformly. As shown inaccordance with the present embodiment, the printer filament 14 is aconsolidated printer filament.

A non-reinforcement component of the consolidated printer filament 112,or the matrix 114, contains the fiber filaments 111 in such a way that,preferably, the fiber filaments 111 are not in contact with one andanother (that is, there is matrix materials between adjacent fiberfilaments) and spacing between the fiber filaments 111 is minimized,thereby maximizing the density of the fiber filaments 111 within thematrix 114.

With close-packing of the fiber filaments 111, fiber filaments 111 canfill about 90% of a volume of the printer filament 112. However, thevolume of reinforcement material in the consolidated printer filament112 is typically less than 90% of volume. Percent volume and percentweight of the fiber filaments 111 within the printer filament 112 areused interchangeably herein as is common when discussing composites.However, this is technically slightly incorrect since density insemi-crystalline thermoplastic polymers varies as a function of percentcrystallinity (crystalline phase is denser). Nevertheless, this minutevariation is insufficient to detract from conveying the relevant ideas.In case the structure of the consolidated printer filament 112 is stillunclear, a cross-section view is provided in FIG. 14.

In operation, the printer filament 112 is passed through the nozzle 10with a similar mechanism as described in reference to FIG. 9, howeverthere is no constriction 100 in the present embodiment. Therefore, theconductive heating mechanism 92 may be difficult to implement and otherheating mechanisms may be preferred. Some such alternate heatingmechanisms include radiative heating with laser, microwave infrared, orother radiant energy, or convective heating by application of a heatedgas. Inductive heating can also be used if there is a conductive fiberfilament or if the overall printer filament 112 is conductive. Anycombination of these heating methods could be used as well. Theconsolidated printer filament 112 is fed from the nozzle 10, typicallywith controlled movement. The present embodiment can be used as acomponent in an additive manufacturing system.

Referring next to FIG. 10A, a perspective view is shown of a nozzlerotational assembly showing independent shafts for filament feeding andnozzle 10 rotation.

Shown is a main shaft 270 and a secondary shaft 272, with respectiveinput wheels 271, 273; two drive wheels 274; shown is a nozzle 10 andnozzle housing 20.

The secondary shaft surrounds a portion of the main shaft. Each shafthas an input wheel on one end. Both shafts pass through one wall of thenozzle housing, and only the main shaft extends through the oppositewall of the nozzle housing. One drive wheel is on the end of thesecondary shaft within the nozzle housing, and the other drive wheel isnext to this one such that they contact at a point if one were toconsider these wheels infinitely thin, or at a line if they havethickness and a constant diameter throughout, which might not always bethe case. There is also a small gap between the two drive wheels, whichcan have a zero, positive, or even negative size with an interferencefit of an elastic material. The drive wheels are within the nozzlehousing. The nozzle extends downward from the base of the nozzle housingwhere it is mounted.

This system discloses how to decouple an additional axis in thethree-dimensional printing system, where the additional axis comprisesrotation of the nozzle about an axis perpendicular to the central axisof the nozzle, from the feeding mechanism for the printer filament. Thisenables the nozzle to rotate without yanking the filament from the partin a way that would ruin the print and possibly damage the nozzle.Furthermore, it enables rotation of the nozzle along with precisefilament feeding that does not allow excessive slack in the post drivesection of the printer filament, and this prevents buckling andsubsequent jamming of the printer filament.

The input wheels 271, 273 allow the shafts to be independently rotated.Rotation of the main shaft rotates the entire nozzle housing since it isfixed at the nozzle housing wall opposite the input wheel. The secondaryshaft can rotate freely with respect to both the nozzle housing and themain shaft. This enables a rotation of the secondary shaft input wheel273 to rotate the secondary shaft along with one of the drive wheels274. The rotation of the drive wheel 274 that is connected to thesecondary shaft causes the other drive wheel 274 to rotate in the otherdirection. The two drive wheels 274 can effectively drive a printerfilament from a spool into the nozzle 10. The feeding rate can bemodulated in conjunction with the movements of the nozzle tip duringprinting, which enables a particular tension to exist in the printerfilament.

Referring next to FIG. 10B, a cross-section view is shown of a nozzleradiative chamber 278 and associated energy sources 286. Shown is thenozzle end 102; the flanges 280 of the radiant chamber of the nozzleend; the end 282 of the cooling chamber of the nozzle shaft; the end ofa filament guide tube 284; two circles 286, representing a radiantheating source; and a radiation sensor 288.

The radiative chamber flanges 280 comprise the outer structure of thenozzle end 102. The end of the cooling chamber 282, which comprises themain nozzle shaft, extends downwards into the radiative chamber 278along the outside of the filament guide tube 283. The filament guidetube passes through the radiative chamber 278 and protrudes below theflanges 280 of the chamber. The radiation sensor 288 is positionedfacing inward in the radiation chamber 278, attached to the inner flangewall, or in an optically equivalent or proportional location.

The radiation source 286 emits radiant energy, or it may represent anopening in the radiation chamber 278 into which radiant energy isdirected. Methods of obtaining suitable radiative energy includes lasersor heating filaments, or other materials such that they radiate as ablack body radiator. Heating filaments such as tungsten could be usedwhile embedded in a ceramic. Heating elements in lightbulbs such ashalogens or other lights would also be effective. A radiant sourceexternal to the radiative chamber is beneficial since it enables thediameter of the nozzle end to be greatly reduced, which enables anarrower nozzle for greater geometric mobility in multiple axes.

Except for the filament guide tube 283, it is beneficial that thesurfaces of the interior of the radiative chamber are highly reflectiveacross whatever frequencies are being used. The filament guide tube 283is made of a radiatively transparent material to enable the radiation tohit the printer filament, which the carbon fiber effectively absorbs andtransfers to the matrix material, allowing it to flow and bond to thebuild plate or previous layers of the part. The extension of coolingchamber along the filament guide tube 283 enables this radiativeabsorption to be concentrated and take place near or after the end ofthe filament guide tube 283. Efficient reflection of radiation enablesthe radiative chamber to minimize heat absorption, which in conjunctionwith active cooling, ensures the heat does not rise.

The filament guide tube 283 is shown to contract near the end 284, whichwhen operated with a continuous fiber reinforced printer filament 112will have a final exit diameter equal or nearly equal to that of theinput printer filament. This has the benefit that the filament 14 caneasily pass through the filament guide tube 283 prior to the heatingzone 278 with minimal resistance. It is beneficial that the filamentguide tube 283, in addition to being transparent to radiation, berefractive. This enables the filament guide tube 283 to operate as thetip of the nozzle during a printing operations. It is also beneficial ifthe tube has poor thermal conductivity to limit upward heat flow sincethe tube contacts the heated section of the printer filament near thetip. Any non-radiative heat transfer method would likely have to beconductive and therefore by unable to limit upward heat flow as much asthe various designs that embody these disclosures.

It is beneficial to precisely control the amount of heat transferredinto the filament 14 as it passes through. Excessive heat damages oreven burns the thermoplastic, and insufficient heat results in poorbonding. Thermistors on an outer surface do not correspond directly toheat input into the filament, and due to variation of resistivity ofresistive radiation heating elements (if that is the type of heatingelement), and the fact that temperature 4th power of the temperature ofthe radiative source is related to the output power in the 4th order,controlling heating output by varying current and voltage withoutadditional feedback cannot achieve the same precision as a radiationsensor. With other radiative heating elements, a radiation sensor 288 isalso extremely precise. This precise feedback control loop enables thefunctionality of the overall nozzle 10 during printing. This is becausethe radiation (in part) hits the filament 14 just as it exits the nozzle10, and passing through an opening means that the radiative efficiencywill vary based on how ‘closed’ this exit is. Therefore, the sensor 288enables measurement of the precise amount of radiant flux that isdelivered into the filament. This enables superior interlayer adhesionsince the filament can be made to reach the maximal melt temperaturethat does not cause damage without a risk of burning the filament.

Referring next to FIG. 10C, shown is a cross-sectional view showing aliquid cooling chamber 290 (cooling mechanism) within the nozzle 10.

Shown is the nozzle 10; a cooling chamber 290; the nozzle end 102; twoinlets 292; and a filament guide tube 283.

The nozzle 10 comprises an assembly of the other pieces shown. The twoinlets 292 connect to the cooling chamber 290. The nozzle end 102 isattached below the cooling chamber 290, and the filament guide tube 283goes through the cooling chamber 290 and the nozzle end 102.

In operation, the cooling chamber 290 is filled with a cooling fluidsuch as water, which enters through one inlet 292 and exits the other.It is beneficial if a pump is used to cause an active flow of thecooling fluid. This system is beneficial in enabling thethree-dimensional printing of a composite filament 14 without the needfor a melt-pool. Obviating the need of a melt-pool enables higher fiberto matrix ratios to be used since the filament can be wet-out in priorprinter filament processing steps to ensure that there are not excessivevoids or fiber clumping within the printer filament. This cooling systemenables the portion of the printer filament in the filament guide tubeabove the printer end to remain at a lower temperature, which preventsbuckling, and enables active feeding of the filament with some amount offorce rather than operating purely in tension. This active feedingmechanism is disclosed in FIG. 10A.

By preventing excessive upward heat flow from the nozzle end, thisactive cooling system has the benefit of enabling a higher aspect rationozzle to be implemented. It is particularly beneficial to have a nozzlewith a high aspect ratio when three-dimensional printing with 5 axessince it expands the angular motion that the nozzle can undergo withoutrunning into the part or build plate. This cooling system isparticularly beneficial when using continuous carbon fibers since thisgreatly decreases the thermal resistivity along the length of theprinter filament. Finally, the cooling system, by ensuring that heatingof the printer filament occurs primarily at the nozzle end, minimizesany possible thermal damage to the thermoplastic matrix material.

Referring next to FIG. 11, a cross sectional view is shown of a printerfilament 14 that is a consolidated printer filament 112. A larger circle116 represents the cross section of the printer filament 112, and smallcircles 111 within the larger circle represent fiber filaments 90.Parallel cross-hatching 114 within the larger circle 116, the bitoutside the smaller circles (i.e., in the volume between the fiberfilaments) represent the polymer matrix 114.

The circles 111 show a near uniform distribution of the fiber filamentacross the cross-sectional volume of the printer filament 112.Furthermore, the polymer matrix 114 fills all gaps between the fiberfilaments.

This is the same consolidated printer filament 112 of FIG. 10, shown isa cross-sectional view. In accordance with the present embodiment,having a sheath (not shown) of the polymer matrix surround a bundle ofthe fiber filaments as a core shell structure, with the polymer as theshell and the fiber filaments as the core, is not desirable and resultsin very poor properties.

If the polymer matrix 114 surrounds the fiber filament 111 in a bundlethat forms the fiber tow only as an outer layer with little penetration,loads cannot be effectively transferred to or between the strong andstiff individual fiber filaments. Furthermore, uncoated individual fiberfilaments in the core are not protected from damage due to fiberfilaments abrading against one another since fiber filaments are fragilewithout the protection of the polymer matrix. Failure to have all fiberfilaments coated can lead to premature part failure and low durability.Having the polymer within the gaps between strands of the fiberfilaments 90, and not just enveloping the bundle of fiber filamentsmeans that one obtains the full benefits of reinforcement of the fiberfilaments rather than a marginal improvement over neat polymerproperties. This structure is particularly beneficial for functionalparts that are subject to repeated stress or are in failure criticalapplications since having the polymer distributed within these gaps isnecessary for adequate fatigue resistance. It is also beneficial inpreventing damage from impacts.

Referring next to FIG. 12, a schematic view is shown of a nozzle 10 witha Cartesian set of coordinate axes 120.

The nozzle 10 is shown pointing in a direction of the XY plane andsuperimposed in three additional locations 121, 122, 123 as indicated byarrows and dashed lines 124, 125, 126.

In operation, the nozzle 10 is moved in three dimensions, as measuredalong the 3-axes 120, as can be performed in an additive manufacturingmachine of the present embodiment.

Referring next to FIG. 13, a schematic view is shown of an arm 130, ajoint 132, and the nozzle assembly 20. A round build plate 42 is alsoshown.

The nozzle 10 is shown rotating through three angles 134, 136, 138,partially indicated by dashed lines 134, 138.

The nozzle 10 is part of a nozzle assembly 20, and attached to the arm130 with a connection at the joint 132. Arrows are used to indicaterotation of the nozzle 10. Other arrows on the build plate 42 showrotation of the build plate 42 around a center point.

In operation, this demonstrates how two axes 120 in addition to thethree Cartesian axes shown in FIG. 12 are implemented in accordance withthe present invention. The rotation of the nozzle 10 and build plate 42is controlled in conjunction with the movement illustrated in FIG. 12 toenable full five axis movement of the nozzle 10. The benefits of theseadditional two axes 120 is described in reference to the embodiments ofFIG. 7 and FIG. 8. The benefits generally relate to the augmentedengineering capabilities from not only being able to have a nozzle 10take an arbitrary path, but to do so with an arbitrary set of anglesalong that path, which is a critical step necessary to form complexconformal layers 50 that tend to exist in optimized parts.

Referring next to FIG. 14, a perspective three-dimensional view of asurface is shown. A set of Cartesian coordinates 30, the surface 16, anda projection 140 is shown.

The surface 16 exists within the coordinate space and the projection 140is that of the surface 16 onto the XY plane.

In the additive manufacturing process, surfaces such as these may occurwhich can only be formed by traditional 3-axis printers by followingcontour lines. Lines that follow arbitrary paths can however be formedwith a 5-axis printer of the present embodiment.

The additional axes described in FIG. 13 allow filaments to conform toarbitrary surfaces instead of the single flat surface 142 of the XYplane to which 3-axis printers are limited.

Referring to FIG. 15, a nozzle assembly 20 is shown with the nozzleassembly 20 shown at two points 134, 138 in time. Shown is the rotationjoint 132 of a device 130 that holds the nozzle 10. A 2-dimensionalslice of a set of conformal printer filament 14 layers 50 is also shown.

The device 130 that holds nozzles 10 holds the nozzle assembly 20. Thetwo points in time shown with an arrow illustrating movement of thenozzle 10. The printer filament 14 layers 50 form a part 48.

In operation, the nozzle 10 is able to form conformal layers 50 becauseof the two additional axes of movement as between stacked 2-dimensionalmovements to 5-dimensional movements. These conformal layers 50, beinganisotropic, especially if they comprise a reinforced printer filament14 or a consolidated printer filament 14, result in a part 48 whoseproperties differ from those of a part 48 filling the same volumeprinted from stacked 2-dimensional layers 50. Being able to vary theproperties in this way is beneficial in improving the performance of thefinal parts that an additive manufacturing machine, of which this systemcan be a component, of can produce. This figure highlights some of thebenefits of one of the additional axes 120 that can be included inaddition to X, Y, and Z. Another benefit is that even if a similarsurface could be produced solely with X, Y, and a more sophisticated Zaxis, this additional axis 120 allows more complexity in the form ofsmaller feature details. FIG. 6 shows how even a relatively wide shapemight not be able to be produced with conformal layers 50 since thenozzle assembly 20 would hit the part 48. Nozzle 10 rotation inconjunction with software that considers the shape of the part 48 andthe space taken up by the nozzle 10 allows various parts that would beunprintable using additive manufacturing systems without this feature.

Referring to FIG. 16, a perspective view is shown of a nozzle assembly20, a build plate 42, and a printer filament 14.

The printer filament 14 is in a coil shape on top of the build plate 42,and the nozzle 10 positioned above the end 150 of the printer filament14.

In operation, a typical additive manufacturing machine is able to create2-dimensional layers 50 by 2-dimensional movement of the nozzle 10,where this movement can be considered with respect to anythingstationary, which would include the build plate 42. However, if thebuild plate 42 rotates, either the X or Y axis in conjunction with thisrotation can form any 2-dimensional layer. However, rotation and linearmovement, when reduced to practice might be able to execute the samepath in different amounts of time. With the rotation, X, and Y axis allsimultaneously in operation, the fastest possible relative movementsbetween a point on the built plate and the nozzle tip 100 may beachieved for any fixed level of print quality that one needs to achieve.Complex movements with many changes in direction tend to slow down theprint rate and as more complex shapes are produced with a 5-axismachine, it is beneficial to enable the fastest possible movement sothat parts can be manufactured in the shortest possible time. There mayalso be benefits in complexity of paths that are feasible with combinedmovements.

Furthermore, when one considers the Z axes 120 movement, which is thefirst axis to be mentioned within this description, it becomes apparentthat the build plate 42 rotation enables print paths along arbitrarycurves in a 3-dimensional space that would otherwise be highlyimpractical or impossible. This might be particularly beneficial if thepart 48 is to be produced with layers 50 of printer filament 14 thatwrap around the part 48. Other figures such as FIG. 18, FIG. 19, andFIG. 20 that illustrate the fiber orientation at a smaller scale showthe great benefits of being able to print along these complex rotationalpaths due to the large degree of printer filament 14 anisotropy, whichparticularly relevant when the printer filament 14 is a reinforcedprinter filament or a consolidated printer filament. When the termorientation is referred to herein in regards to printer filaments thatare reinforced printer filaments it refers to the printer filamentsorientation, which is specified to distinguish it from orientation ofshort reinforcements within a reinforced printer filament.Inner-printer-filament orientation distributions are often approximatelyradially symmetric and thus can still be modeled by defining the on-axisand off-axis properties of that reinforced printer filament.

Referring next to FIG. 16A, is a perspective view showing an interfacebetween spring-loaded contact and slip rings. Shown are a plurality ofslip rings 52, a plurality of springs 54, a plurality of rocker arms 56,and a plurality of electrical contacts 58; shown is a housing 60 and ahousing cap 62; shown is a central shaft 64.

The central shaft is positioned on the housing and is covered by thehousing cap. The slip rings are axially aligned with the central shaftand are stacked and spaced along the central shaft within the housingand housing cap. The electrical contacts are each adjacent to one of theslip rings. The springs are attached to the upward rising arm of thehousing on one side, and on the other connect to the end of the rockerarms that connects to the electrical contacts. The other end of therocker arms is held on a pin 66 in between the housing and housing cap.

In operation, this interface allows the transfer of energy to acontinuously rotating build plate. Each spring and rocker enablescontinuous contact of the electrical contacts with the slip rings toallow uninterrupted electrical energy transfer. This enables the centralshaft to continuously rotate, which enables multiple useful printingoperations such as winding.

Referring next to FIG. 16B, a cross-sectional view is shown of a buildplate assembly 69 showing material composition of each layer, the slipring assembly of FIG. 16A; a plurality of cables 68; a build plate 69; atop layer of the build plate 72, a heating layer 74, a thick insulatinglayer 76, and a final insulating layer 78.

The slip ring assembly 69 is positioned below the build plate 69. Thebuild plate 69 is attached to the slip ring assembly 66 by being fixedto the main shaft 64 of the slip ring assembly 66 that is disclosed inFIG. 16A. The final insulating layer 78 is positioned on the bottom ofthe build plate 69. Directly above that is the thick insulating layer76. Above the thick insulating layer is the heating layer 74, and abovethat is the top layer of the build plate 72.

In operation, this system enables effective heating of the build platein conjunction with continuous rotation. The multiple insulation layersand thickness of the thick insulating layer enable higher surfacetemperatures on the build plate surface 72, which is beneficial forthree-dimensional printing materials with high temperaturethermoplastics such as polysulfones, polyimides, orpolyaryletherketones. The top layer 72 can be a metal or metal alloysuch as aluminum or steel. On top of the top layer, a coating can beapplied to improve build plate adhesion during printing. This coating istypically a thermoset polyimide adhesive backed sheet, or an adhesive ormelted on sheet of the same thermoplastic that is being printed or onethat is thermally bondable to the material being printed. Othermaterials are also contemplated for the top layer of the build plate.Ceramics (e.g. graphite), ceramic metals (e.g. tungsten carbide orsilicon carbide), or metalloids (e.g. silicon), or a combination ofdifferent materials to form a multi-layer ‘top layer’. The use of thesematerials are beneficial in ensuring effective and rapid heat transfer,thermal stability, non-warping, and possibly even adhesion without theaforementioned additional coating, and such a system would beneficialallow rapid swapping of a thin plate that comprises the top plate of thetop layer as might be implemented in an automated, arbitrarily largeparallel manufacturing facility.

The heating layer 74 can be any number of heating elements such asnichrome wire, an induction heater, a resistive plate heater, an openflame heater, a digitally controlled frame, infrared radiation ormicrowaves. The thick insulating layer 76 can be an air gap, but it isbeneficial to fill this space to reduce or eliminate convective coolingof the heating layer. Suitable materials include mineral wool, asbestos,foamed silica, fiberglass, or Nomex. These materials are beneficialsince they have low density, which enables rapid acceleration of thebuild plate. The final insulating layer can be made of concretefiberglass composite with refractory high temperature sides, and unlikethe thick layer, it is beneficial for this layer to have greaterrigidity. The slip ring assembly allows the heated layered to be poweredthough wires 68 passing through the build plate 69 through the mainshaft 64.

Referring next to FIG. 17, a perspective view is shown of a nozzleassembly 20, build plate 42, printer filament 14, andprinter-filament-comprised sub-part 48.

The perspective view is looking down at the build plate 42 with theprinter filament 14 comprised sub-part 48 shown with contour lines. Theprinter filament 14 is connected to the base of the part 48 at an edgethat connects to the build plate 42 on one end, and the other end isgoing into the nozzle 10.

This figure is similar to that which was described in FIG. 16, but itshows another example of how the rotation of the build plate 42 might becombined with movement in X, Y, and Z. Of course, there exist parts inwhich these four 120 plus the rotation of the nozzle 10 from FIG. 15would be implemented.

Referring next to FIG. 18, a perspective view is shown of arepresentative volume of a continuous fiber reinforced polymer composite182 that could be produced from consolidated fiber filaments 112. Fiberreinforced polymer composite is a term that is known in the art and itis an apt term to describe the product of some of the manufacturingmethods of the present embodiment.

The volume is shown with arrows that indicate the 6 primary forces thatcan act on the volume: 3 tensile forces (negative is compression) andshear in the 3 planes.

In many mathematical models of solid objects, representative volumeelements 190 are considered. There are various theories that make aconnection between the properties of such an element and the bulkproperties of a structure comprising these volume elements. This block,being comprised of continuous unidirectionally reinforced fiberfilaments 111 is anisotropic, meaning the properties vary based on thedirection. In fact, this type of structure is not fully anisotropic, butis known as transversely isotropic since it has one axis of symmetry. Itis worth noting that short reinforcements could be approximated astransversely isotropic, though the short reinforcements do not exhibitisostrain at a micro-level. See FIG. 19 for more details. The mechanicalproperties along the reinforcement axis can easily end up being an orderof magnitude higher than the directions orthogonal to the reinforcementaxis or continuous fiber axis. As such, models that utilize this sort ofrepresentative volume 182 element cannot simply create a mesh that asksif there is or is not material at a given location, the model must alsotake into account the angle of the fiber filaments 111 in that element,and these angles may be continuously varied throughout the part 48, asdetermined by the printer filament 14 orientations.

Even for printer filaments 14 that are not reinforced printer filamentsand are also not consolidated printer filaments, i.e., for printerfilaments 14 that include only the matrix 114, the transverselyisotropic nature of the printer filament 14 must be considered because:(1) the production of polymeric filaments (depending on the material)may have a tendency to align polymer chains causing a similar effect ascontinuous reinforcement or short reinforcement especially if liquidcrystalline phases are present; (2) imperfect bonding between printerfilaments in parts means that off-printer filament axis properties canbe weaker than on-printer filament 14-axis properties. However, withoutcontinuous fiber reinforcement or short reinforcement this might only bea small factor and the parts could be thought of as equally bad in alldirections. The printer filaments described herein that are reinforcedprinter filaments or are consolidated printer filaments benefit fromhaving the part 48 models and subsequent print paths consider theanisotropy. This is beneficial because it allows substantial improvementnot solely along one direction, but improvement of properties in anydirection that one wants. Furthermore, it is because of the 5-axes 120of the disclosed additive manufacturing systems that these benefits canbe realized in conjunction with novel computational techniques thatgenerate novel physical structures.

Referring next to FIG. 19, a perspective view is shown of threerepresentative volume elements 190, 192, 194. Short reinforcement fiberfilaments 90 are shown. Cartesian coordinates 30 are also shown.

The short reinforcement fibers 90 are aligned within each volume elementand the volume elements are each aligned with one of the axes 120 shown.

These elements are similar to those from FIG. 18. The shortreinforcements do not meet the isostrain condition, but the reinforcedprinter filaments 14 that comprise short reinforcements will still haveproperties that are well defined along the primary loading paths. Sinceshort reinforcements are not continuous, they do not have isostrain at amicro-level because for a uniform stress field, polymer sectionsadjacent to reinforcement sections will have greater reinforcement thanthose polymer sections that might be in between reinforcement ends at alocal scale. However, in macroscopic parts these effects average out,but must still be considered in order to accurately predict the bulklevel properties. The elements shown can be thought of as a projectionof any single element in an arbitrary orientation. That element thenexists properties of all the individual elements to varying degreesproportionally to the amount of alignment.

Referring next to FIG. 20, a perspective view is shown of printerfilaments 14, aligned along three axes.

A structure is formed from the printer filaments 14. The figurecomprises three sections with printer filaments 14 substructures inthree different alignments.

The right side of the figure shows a layer 50 of vertically alignedreinforcement material. On the bottom and top of the left side of thisfigure are short reinforcements that go into and out of the page asindicated by showing the ends of the short reinforcements. The layers 50in between those are separated by a gap and have reinforcements that goleft and right. Together, the layers 50 on the left side are essentiallytwo 2-ply laminates that are separated from each other. Thesesub-laminates may have any orientation, but the 90-degree offset waschosen arbitrarily to illustrate a particular mechanism. It is worthnoting that in this structure, the reinforcement may be continuous,discontinuous, or not at all, in which case the intrinsic printerfilament 14 transverse isotropy inherent to these anisotropic systemsmay still be marginally relevant.

In operation, this figure can be seen as implementations of aspects ofthe representative elements of FIG. 18 and FIG. 20 in conjunction withthe design freedom enabled by the various elements that comprise thesesystems of 5-axis additive manufacture of transversely isotropicfilaments. This particular structure was chosen to illustrate specificaspects of these systems which are beneficial, but of course there arevarious other aspects that can be formulated through the computationalmethods suggested herein that would consider the novel representativevolume 180 in conjunction with the manufacturing process.

The figure shown is not only is beneficial for the field ofmanufacturing, but also provides a mechanism to solve some of theproblems that have plagued the composites industry for decades. Thisfigure demonstrates how multi-axially printed composites may beeffective in preventing delamination. Both in additive manufacturing andcomposite manufacturing, parts are produced layer by layer. Sincecomposites typically have strong reinforcement materials, but arelatively weak matrix, this means that excellent planar properties maybe achieved, but the through thickness properties are vastly limitedsince the reinforcements do not provide much reinforcement when loadedorthogonally to their length. Therefore, composites layers 50 mayseparate causing part 48 failure and engineers are limited in theirdesign because they must account for this. Furthermore, there is alimitation to creating parts that are essentially curved planes sincethe mechanical properties are only good in the plane. It is highlyimpractical to create bulk three-dimensional composite structures withsuch layers 50 that are effectively reinforced in all directions so manyparts are instead made of inferior metallic materials.

This figure on the left solves these problems. By being able to orientfilaments along any direction, the reinforcement fibers 90 can go in alldirections in a bulk three-dimensional part 48. Then anywhere that mightdelaminate, consolidated printer filaments or reinforced printerfilaments with reinforcements orthogonal to that delamination plane canbe placed that will arrest propagation of a crack, and thus preventcatastrophic part 48 failure. Furthermore, the part 48 can be strong andstiff in any direction that is needed instead of just in a plane. Onemight observe that this figure can be viewed as a composition of threerepresentative volume elements 190 as described in FIG. 18 and FIG. 20,and this configuration shows substantial benefits over existing options.When used in conjunction of computational optimization and possiblygenerative design, many more such sub-structures with beneficialproperties arise and the applications of these materials expand not onlyfor additive manufacturing, but manufacturing in general.

Referring next to FIG. 21, a perspective view is shown of a structurecomprised of printer filaments 14 that could be either reinforcedprinter filaments or consolidated printer filaments. The figure does notshow the structural arrangement of the individual printer filaments. Thefigure shows the path a crack 210 might follow if the part 48 underwentfracture.

This figure illustrates a lamina of filaments that are parallel withineach layer and then rotated by some angle in each subsequent layer. Thecrack 210 shown is a helical curve that passes through inter-printerfilament 14 gaps in each layer without splitting any individual printerfilament 14 along its length. Although such a crack 210 path could alsosplit individual printer filaments 14, it is less likely given thatinter-printer filaments are often not as well adhered as the bulkmaterial (see FIG. 36 illustrates an exception to this heuristic). It isworth noting that in this structure, the reinforcement scheme may becontinuous, discontinuous, or unreinforced, in which case the intrinsicprinter filament 14 transverse isotropy inherent to these anisotropicsystems may still be marginally relevant.

This figure can be seen as implementations of aspects of therepresentative elements of FIG. 18 and FIG. 20 in conjunction with thedesign freedom enabled by the various elements that comprise thesesystems of 5-axis additive manufacture of transversely isotropicfilaments. This particular structure was chosen to illustrate aparticularly beneficial aspect of these systems, but of course there arevarious other aspects that can be formulated through the computationalmethods suggested herein which would consider the novel representativevolume 180 in conjunction with the manufacturing process.

This figure solves a critical problem faced by composites manufacturers.This figure is merely another example of the benefits of complexorientations, this one benefiting from the material anisotropy, andproducible with only three of the five axes 120. First, some backgroundinformation: Fiber reinforced polymer composites are known for havingextremely high specific strength and specific stiffness compared toother material choices such as steel, aluminum, or even titanium alloys.However, their weakness is their relatively low toughness, especiallywhen the polymer is a thermosetting matrix, which has dominated thecomposites industry due to its ease of processability compared tothermoplastics (some of the later printer filament 14 figures willdiscuss how the systems described herein also beneficially increase theusability of thermoplastics in composites). Various tougheningmechanisms have been developed to lessen this problem, but it is stillthe case that dropping a wrench in a composite airplane or crashing on acarbon fiber bicycle could cause irreparable damage due to the inabilityof composite to absorb the impact energy, the very definition oftoughness. This has an associated component of energy absorption underfailure. For instance, in an automobile with a primary compositestructure undergoing a collision may fail suddenly, essentially, theopposite of what a crumple zone does. It would be beneficial to extendthe time in which the material fails since distributing impacts in timereduces peak acceleration, which has been shown to be beneficial forhumans.

The structure shown in this figure, which can be produced from thesystems described herein shows how all these problems could be overcome.Traditional composites are made with a small number of angles for theunidirectional lamina since it is difficult to work with small angles.An additive manufacturing machine can easily shift by a small angle toform a helical composite. This helical composite then might have a crack210 that follows a helical curve, which has a greater surface area thana flat curve for any given volume. Fracture energy released duringfracture is related to the strain energy release rate, which isproportional to the energy in forming new surfaces, which isproportional to the surface area. Furthermore, these structures canabsorb more elastic energy without fracture or developing ofmicro-cracks that compromise a part's structural integrity, which isclearly a problem in composites as shown by the decrease in compressionstrength after an impact. The formation of composites with complexorientations such as these, which may be extended to incorporate thecapabilities of the additional two axes 120 will be able to produceparts tougher than those produced by any existing process.

Referring next to FIG. 22, a flow diagram is shown.

Each block of the flow diagram can be considered a piece. Arrows connectthe blocks and one block has two arrows with Boolean values of ‘yes’ and‘no’ to determine which arrow to follow.

The first block is a CAD part design 1000, which is input into a slicer,the output of which is input into a FEA. The output of the FEA is inputinto an optimal test. If the output of the FEA is optimal, the FEAoutput is sent to the additive manufacturing machine. If the output ofthe FEA is not optimal, the process modifies the geometry, and outputsthe modified geometry to the slicer.

In operation, this flowchart is one implementation of a computationalstructural optimization system that can be used to produce anisotropicadditively manufactured parts optimized for some plurality ofobjectives. This process begins with a CAD part 48 that could either beproduced by a person or by a generative design process. The slicer 1002generates a path that would allow the additive manufacturing machine toform the geometric part 48. The slicer 1002 has heuristics regardingprinciples of structural design. For instance, the slicer does notsuggest the collection of parallel layers 50 used in typical 3-axisprinters since this has terrible z-directional strength, impacttoughness, and delamination resistance. Instead the slicer creates apath that is good for many situations that balances conflictingobjectives. This slicer step alone might be sufficient for someapplications, but it is not likely to be fully optimized for theparticular application.

The subsequent step suggests finite element analysis (FEA), but thiscould be any sort of analysis on the structure suggested by the slicerto determine if it meets some criteria or where the primary weaknessesare so those can be improved. The next step is checking whether the FEAshowed acceptable performance. If the structure is adequate, the path issent to the printer to produce the part 48. Otherwise, the process goesto a perturbative step that changes the geometry in order to move closerto a design that is optimal for the given application. This perturbeddesign is fed back into the slicer. This is a feedback loop where manyminor changes can quickly change the design with consideration for themanufacturing constraints of the printer to arrive at highly optimizedparts. Other optimization processes can also be used that iterativelydiscover the best part 48 structure and path to form the structure. Itmay be beneficial to use multiscale models.

Referring next to FIG. 23, a perspective view is shown of a fixed wall230, a mesh 232 and a load 234.

The mesh 232 extends out from the wall and the load 234 is directeddownwards at the end of the mesh 232 on the side farthest from the wallas indicated by the force vector.

This represents part of the design process in accordance with oneembodiment for generating a print path for a final part 48. The mesh 232is the geometric boundary within which the part 48 must be contained.The area where the mesh contacts the wall is where it would be joined tosome other structure. The load 234 is that which the part 48 needs towithstand in operation. The mesh 232 forms unit cells, each of which canbe filled with material or be empty. The angle of reinforcements withinthe unit cell is variable. The unit cells can be considered at multiplescales. For example, a unit cell can be an arrangement of the most basicunit cells that is constructed to be quasi-isotropic and able to tilethe volume. Multiscale models can beneficially achieve greateroptimization when computational resources are limited. It needs to benoted that the unit cells are not independent since the structure, orsubstructure, needs to be connected and possible to manufacture with theadditive process. Therefore, a complex systems approach can be employedfor effective topological optimization.

Referring to FIG. 24, shown is a loading configuration with two fixedpoints 236 and one load 234. Shown is an example with the likeness ofone, which may arise from a topological optimization.

The generated structure rests on the two fixed points 236 and supportsthe downward load 234.

This is an example of what a simple topological optimization schemewould create. Beginning with just the fixed points 236 and load 234, thesoftware would generate some optimal structure. This figure does not infact show an exact representation of the actual structure that would begenerated. The actual structure would take into account not just anyform of arbitrary unit cells with some set of microscale materialproperties such as those described in FIG. 23, but optimization processwould generate structures that are compatible with the additivemanufacturing machines described herein.

Referring next to FIG. 25, shown is an abstract representation 250 of astructure that represents a gradient property throughout a structure.This is depicted by showing a variation in relative density. Shown is aone-dimensional scale with the labels “hi” and “lo”.

If the property being varied in relative density is a cellularstructure, each vertical bar could be solid material with the lines ontop and bottom also solid material so that the part represents aconnected structure. The “lo” indicates the direction in which aproperty decreases, which is shown to be the direction of increasingspacing between solid parts of the structure.

Functional gradation describes a non-homogeneity of some aspect of acomponent, where the aspect might be deliberately varied to benefit theoperation of the final part 48. The figure shows a change in relativedensity, but the part 48 can be functionally graded with any property,which would typically be controlled by manipulation of the componentstructure. Thus, aspects of this figure might be incorporated intocomputational design systems described in FIG. 22, FIG. 26, and FIG. 27.Functional gradation beneficially allows the minimally sufficient amountof material to be used to achieve the design constraints, and can alsobeneficially enable unique properties such vibrational damping, whichwould have acoustic implications as well, and absorption ofelectromagnetic radiation in stealth applications, among others.

In the same way a bridge has beams in some places and other places areempty, it is desirable to have parts with a similar sort of‘micro-architecting.’ When relative density is varied, it allows designconstraints to be met with less overall material, or improvement inperformance at the same weight by varying where the material is placed.Another benefit would be considering energy absorption in plasticfailure of the overall part.

These are some of the mechanical properties one would consider whenfunctionally grading a part and non-mechanical properties could also beoptimized.

Referring next to FIG. 26, shown is a schematic diagram of a device 152that transmits information in a primary visual mode, for example acomputer monitor 260.

Shown displayed on the computer monitor 260 are a plurality ofattachment points 154. Also, shown displayed on the computer monitor 260are a plurality of vectors 262 and moments 264.

All elements described in reference to FIG. 26 that are not the computermonitor 260 are displayed on the computer monitor 260. It is presumedthat the computer monitor 260 is connected or coupled to a computer,such as a personal computer.

The attachment points 154 and loading conditions are shown on themonitor with forces acting at the attachment points 154.

This represents a computer aided engineering system that enablesgenerative design of components with consideration for themanufacturability constraints inherent in the additive manufacturingsystems described herein. A person designing a component to bemanufactured using the additive manufacturing system and methoddescribed herein first determines how that component would be a fixed toother components of a system and then specifies the loading conditionsthat occur at each attachment point. Next, the designer inputs thatattachment points 154 and loading conditions into the computer and thecomputer generates a part 48 geometry for an optimized design that meetsthe structural requirements. This can be achieved via the use ofintelligent genetic algorithms, neural networks, or purely analyticaldesign, or a combination thereof which uses the constraints the user hasinput to find optimal loading paths through the space in which the partmay exist, and produce more structure where the load is delivered,within some margin of error. This can be achieved by functionalgradation of structure density and anisotropy in given regions of apart, as detailed in FIG. 25. This geometry could include aspects of theslicing technology and integrate with the process described in FIG. 22.This figure describes a system that would replace the initial step ofCAD part 48 in FIG. 22 with the more abstract structural information.Since FIG. 22 begins with some design, it may converge on localmaximums.

The generative process in FIG. 26 represents a larger search space witha greater ability to obtain optimized designs. Various implementationsof this system might include genetic processes, iterative processes, orheuristic processes. Furthermore, the monitor is suggested because it isa common interface between humans and computers. However, there could bevarious other interfaces that will be more practical in the future, andsome that are particularly well suited to these engineering processes.For instance, holographic images or other forms of augmented or virtualreality are a useful visual way to interact with data and part 48designs. Any other interface with other network paradigms could bebeneficial.

Referring next to FIG. 27, a block diagram is shown. There are threeblocks 600 labeled cloud optimization 1014, design 1012, and manufacture1016, respectively. Shown are arrows 800, one of which has the labeldeliver part 48.

The design points to the cloud optimization, representing a designersending out a design, and the optimization operated on the design thatis received. The optimized structure of the design is provided to theadditive manufacturing machine, which produces the part 48. Then themanufactured part 48 is delivered to the original designer.

This figure describes a set of high level operations that could enableefficient industrial implementation of the additive manufacturing systemdescribed so that they can be of the greatest benefit. This system isone that can have varied amounts of automation. In operation, a designis provided, as produced by some method that could involve some aspectsof that mentioned in FIG. 22 and FIG. 26, with the added benefit thatsome components of those figures are implemented in cloud-basedhardware/software systems. Using cloud-based technology has thepotential benefit of adding more computational power to some of theelements that might be included in the optimization process, and thisenables, in accordance with the present embodiment, a greater degree ofoptimization. The present embodiment consists of a front-end softwarewhich allows the user to up-load designs, specify design requirements,and configure constraints on the additive manufacturing process.Portions of this step may be performed by customer servicerepresentatives or engineers, depending upon the customer'srequirements. Then, the part or constraints is obtained from thecustomer, either via automated upload or by personal communication withthe customer. Once the part or constraints have been received, thestructural optimization, generative design, and slicing mechanisms shownin FIG. 22, FIG. 23, and FIG. 24 will be used to generate a printablegeometry and convert the geometry to the finalized part design and“G-Code”.

These computational steps will be performed on higher power, or morecomputationally optimized devices at a location which is remote to theclient, in order to increase the speed of the process and increase thesoftware designer's flexibility. In this system, as soon as the part 48design is finalized, and optionally confirmed by a customer or othermethod, the design can then be produced on an additive manufacturingsystem that might be operating in parallel to many other such systems ina large facility. A finished part 48 or parts is optionally packaged andshipped to the customer. This system beneficially allows one to rapidlychange part 48 designs to create better systems. Furthermore, the systemcan beneficially reduce the amount of engineering expertise to produceoptimized parts, especially if generative design is substantiallyinvolved.

Referring next to FIG. 28, a flowchart is shown comprising labeled boxes600, arrows 800, and Boolean truth values in the form of the words ‘yes’and ‘no’. The labels are specified in the structure.

The connections between the boxes 600 are shown as well as prompts tothe user to determine the path to follow along the flowchart 280. Thefirst step is choose polymer 1018, which points to the question easilyextruded in thin filaments? 1020. If the answer is yes, an arrow pointsto commingled fibers 1022, which terminates the tow. If the response isno, the arrow points to the question highly susceptible to thermaldegradation? 1028. If the answer to the prior question is no, then anarrow points to melt impregnation 1030 and the chart terminates. If theanswer to the prior question is yes, then an arrow points to thequestion can be ground into powder (cryogenic milling)? 1024. If theanswer to the prior question is no, an arrow points to chemicallyreactive process 1032, and if it points to yes an arrow points tosolution process or powder coating 1026.

This flowchart describes a methodology for determining aspects of theprocess to produce consolidated printer filaments that are one of thefeedstock materials for some of the additive manufacturing machinesdescribed herein. Printer filament will be used to refer to arbitraryfilaments. Printer filaments could be ordinary pure polymer filaments,consolidated printer filaments, unconsolidated printer filaments, orreinforced printer filaments. The concepts of a ‘printer filament’ is aconvenient method for referring to the material especially when itsstate may be transferring in some process such as the conversion from anunconsolidated printer filament to a consolidated printer lament.Furthermore, all printer filaments have similarities and many of thedescriptions herein apply to all forms of printer filaments.

The methodology is beneficial when one is considering the use ofdifferent thermoplastic polymers.

For each thermoplastic polymer under consideration, consideration ofwhether such thermoplastic polymer is easily extruded is firstconsidered. If such thermoplastic polymers can be extruded into strandsof polymer filaments, then such thermoplastic polymer can be commingledwith fiber filaments of a fiber tow. Whether the polymer can be extrudedis dependent on its melt-processability, and this data can be obtainedfor common polymers. If the polymer cannot be processed by this method,melt impregnation is used, but this risks thermally degrading thepolymer. If the polymer can be finely ground, powder coating or solutionprocessing are effective. Reactive processing is another method, whichis effective for certain polymers that exist as reactive monomers oroligomers. Reactive processing is different from the other processes inthat the matrix material on the fiber is pre-polymeric and becomes apolymer, usually from heat, and this step might not occur until theconsolidated printer filament 14 is printed. Each of these processes hasdifferent benefits that will be considered subsequently as it isdescribed how each process might be applied to produce the necessaryconsolidated printer filament 14.

Referring next to FIG. 29, a flowchart is shown comprising labeled boxes600 and arrows 800, as well as words near arrows 800. The labels andwords are specified in the structure.

The connections between the boxes 600 are shown to define a processflowchart and words next to arrows specify the form of the material ateach stage. The first set of words are ‘carbon tow’ and ‘polymer “tow”bundled filaments’, which each serve as an input to air jet commingling1034. This first set of words can more generally refer to ‘fiber tow’and ‘polymer filaments,’ respectively, as described previously.‘Commingled fiber’ is output from the air jet comingling 1034 step, andserves as an input to a filament processor (heat, pressure, time, etc.)1036, which generates ‘composite three-dimensional printer filament’(also referred to here as a consolidated printer filament) as an inputto a three-dimensional printing apparatus 1038 (also referred to hereinas an additive manufacturing machine).

In operation, one begins with a carbon tow and polymer filaments. Thefiber tow is commingled 1034 with the polymer filaments, which in oneembodiment is done with an air-jet process. The commingled fibercombines carbon tow and polymer filaments so that they are interspersedas uniformly as possible without excessive processing to avoid fiberfilament breakage. In order to have the commingled fiber, which is asomewhat loose bundle of individual polymer filaments become aconsolidated printer filament 112, the printer filament must be meltimpregnated 1036 such that as many of the fiber filaments 90 as possibleare surrounded by the polymer matrix 114. This is a percolation problemmodeled by Darcy's law, which indicates some combination of heat andpressure, after some time will effectively percolate the polymerthroughout the fiber filaments 90. This process could resemble that ofpultrusion by passing the commingled fiber through a constriction 100along with heating the printer filament 14 by some method.

FIG. 30 and FIG. 31 describe another method by which one might convert acommingled fiber into a consolidated printer filament 112. Commingledfibers are typically woven, but the novel step that converts theunconsolidated printer filament 420 to consolidated printer filament 112is beneficial in that the process is compatible with roller systems bywhich large collimated fiber reinforced polymer rods 88 could not be aseasily produced given their typical much larger diameter. Theunconsolidated printer filament 420 can be thought of as a printerfilament that contains both the fiber filaments and polymer in someform, but has yet to consolidate into a consolidated printer filament.Therefore, the step after commingling is the filament processing step,which effectively consolidates the printer such that the fiber filamentsare distributed throughout the matrix with has few voids as possible.Once this consolidated printer filament is produced, the printer lamentis ready to be used by the three-dimensional printing apparatus.

Referring next to FIG. 30, a perspective view is shown of panels 300,which can be acrylic, a creel 314, which is a reel for fiber tows, andanother creel 316 of a much larger diameter. Shown is an assembly ofrollers 308, 310 and unconsolidated printer filament guiders, tworollers 308, 310, and heating coils 311. Not shown are variousmechanical and electrical components such as motors, circuits, andfasteners.

The panels 300 are joined to form a structure, which in this case is abox. The first creel 314 is fixed within the box at one end and can behold unconsolidated printer filament 420, which may be a commingledfiber. The unconsolidated printer filament 420 may pass from the creel314 over the rollers 308, 310 and wrap around the rollers 308, 310multiple times. The roller guider assembly connects the unconsolidatedprinter filament 420 from these rollers 308, 310 to the larger creel316. This roller creel 316 is positioned on top of the acrylic box.Additional mechanical and electrical components are connected to therest of the apparatus in the way which enables its operation as will bedescribed. There may be heating elements within the rollers 308, 310,and the two rollers 308, 310 may be wired such that the rollers 308, 310are forming a circuit with the unconsolidated printer filament 420 ifthe printer filament 14 is electrically conductive. When carbon fiber isemployed for the fiber filaments within the unconsolidated printerfilament 420, the printer filament 14 is electrically conductive.

This figure illustrates an embodiment of a filament processor apparatusfor performing the ‘Filament Processor’ step described in FIG. 29. Thelower creel 314 will begin with some amount of unconsolidated printerfilament 420 such as commingled fiber and as the printer filament passesover the rollers 308, 310 the printer filament will be heated by aheating element and consolidated. The unconsolidated printer filament420 will be referred to as commingled fiber herein (as well as FIG. 31and FIG. 32). The apparatus shown is the preferred embodiment forproducing consolidated printer filaments. There is no particular amountof commingled fiber necessary, but the amount will typically be at leastseveral hundred feet, and often more. Subsequently, the unconsolidatedprinter filament 420 will become a consolidated printer filament 112 andwill be re-spooled onto the larger creel 316. It is beneficial that thelarger creel 316 be of a sufficient diameter since the wet-out processthat converts the unconsolidated printer filament to a consolidatedprinter filament that has a much larger diameter than that of theindividual polymer filament or fiber filaments that comprise acommingled fiber. As a result, this larger diameter creel 316 is neededto prevent the consolidated printer filament from breaking under bendingstresses. The minimum diameter of the larger creel 316 can be determinedfrom a calculation of the minimum bending radius. Once the consolidatedprinter filament has made a few loops around the larger creel 316, therotation of the creel 314 acts to pull the printer filament through thesystem. This means the rollers 308, 310 and lower creel 314 can be madeto rotate freely.

Various heating methods can be used either individually or inconjunction with one another at the rollers. The coils 311 shown in thefigure are used for inductive heating in accordance with the presentembodiment, which is effective when the individual fiber filaments 90are conductive. However, heating coils 311 are not strictly necessary,and if heating coils 311 are not present, the coils 311 shown should beunderstood to represent the heated polymer filaments, in accordance withother embodiments.

Another heating method suitable for use with the present embodiment isto heat the rollers 308, 310 for conductive heating of with a resistiveheating element.

Another method of heating the polymer filament, when conductive fiberfilaments 90 are employed (carbon fiber filaments are one suchconductive material), is to pass current through the unconsolidatedprinter filament 420 using differing charges on each roller 380 that areprecisely modulated, which beneficially heats each segment ofunconsolidated printer filament 420 between the rollers 308, 310 overthe entire length of the segment. The component of pressure in theprocessing system can result from the tension along the entire printerfilament from the upper creel 316, which presses the printer filamentagainst the roller 306. The roller itself can have smooth groves toguide the printer filament and to allow the individual fiber filaments111, along with the polymer as a polymer filament or in anothermorphology, to spread out over the roller.

Allowing the printer filament to deform into a tape-like shape asprinter filament passes over the rollers 308, 310 can be beneficial inreducing the distance between the polymer and reinforcing fiberenhancing their ability to intimately bond. This tape-like cross sectioncan even be maintained in storing the fiber on creels so that it canhave a smaller bending radius.

Radiative heating can also be employed as an additional method forheating, as can any other practical heating method.

Regardless of the heating method chosen, precise control over the amountof heat that goes into the fiber is beneficial. This is because it isdesirable to have the maximal amount of heat such that the heat is notcausing damage to the polymer since this will give the polymer themaximal fluidity, which decreases the probability of any fiber filamentsthat are not effectively coated with the polymer. Therefore, allparameters that can be easily controlled are controlled with someelectronic system. The electronic system allows parameters including,but not limited to, printer lament tension, speed, and temperature to beadjusted independently. The electronic system ensures that the heat thatgoes into the fiber is sufficient to effectively melt the polymer. Theelectronic system also ensures that the polymer is not heated to anexcessively high temperature that could damage the polymer at amolecular level by chain scission or other heat-related degradationmechanisms.

Referring next to FIG. 31, shown is a perfective view of an apparatushaving two rollers 310, a fiber, and two creels 314, 316.

The unconsolidated printer filament 14 is wrapped around a creel 316with one end making several turns extending along the parallel rollers308, 310 before wrapping around the other creel 316.

This is a simplified view of FIG. 30. The figure shows the essence ofthe functionality and shows how the fiber 112 might be wrapped. Inoperation, a plurality of rollers 308, 310 may be used to transform theloose bundle that is the commingled fiber on the smaller diameter creel314 to the well consolidated fiber on the larger creel 316. Passing overrollers 308, 310 in tension with heat is one such embodiment, but othersare contemplated, and will be appreciated by skilled artisans based onthe description here. Other embodiments optionally have some of theelements of that described in FIG. 30.

Referring next to FIG. 32, a close-up (magnified) view is shown of aconsolidated printer filament 112.

The magnified view shows that within the coiled printer filament 112,the individual reinforcing fiber filaments 111 can be seen continuouslyalong the consolidated printer filament 112.

This figure shows the basic structure of a consolidated printer filament112, but the following is also relevant to reinforced printer filaments298. These consolidated printer filaments 112 are produced by any of themethods suggested in FIG. 28. The fiber filaments have a distributionthat is near uniform with some variation possible due to stochasticityand a tendency for alignment of reinforcements along the center of theprinter filament. Depending on the exact processing method employed, thedistribution can vary. This uniformity is highly beneficial in that thestructure enables many other aspects of the additive manufacturingprocess to work effectively including the part 48 optimization andsimulation processes. Simply having fiber filaments surrounded by apolymer matrix 114 (see the core shell definition provided in referenceto FIG. 11) does not suffice, not only because the core shell structuredoes not allow one to consider a unit cell building block approach incomputational models, but because the core shell structure is alsodetrimental to any part 48 produced. This uniformity of fiber filaments111 or other reinforcements, where the polymer fills nearly all of thespace beneficially allows for the shear force to transfer loads from theweaker matrix to the stronger reinforcement or fiber filament within apart 48, and the complete saturation of the fiber filaments 111 withpolymer 114 helps prevent concentrated point stresses that mightotherwise result in part damage under impact, compression, or repeatedloading that causes fatigue.

Referring next to FIG. 33, shown is a flowchart comprising labeled boxes600 and arrows 800, as well as words near arrows. The labels and wordsare specified in the structure.

The connections between the boxes 600 are shown to define a process andwords next to arrows 800 specify the form of the material at each stage.The first set of words are ‘carbon tow’ and ‘liquid phase polymer(elevated T)’, which each serve as inputs for the filament processor(heat, pressure, time, etc.) 1040. ‘Carbon tow’ and ‘liquid phasepolymer’ should more generally be taken to mean ‘ fiber tow’. Thefilament processor generates a composite three-dimensional printerfilament, and feeds it to three dimensional printing apparatus 1042(another term for additive manufacturing machine), where the arrow islabeled with the phrase ‘composite 3D printer filament 112’ (anotherterm for consolidated printer filament 112).

The filament processor step 1040 can include a plurality of rollers toguide the tow or printer filament 14, some of which can be conicallyshaped with positive curvature outward normal in order to mosteffectively spread the fiber tow. The rollers can have various openingsthat allow the polymer to permeate the tow from the roller side.

In operation, this flowchart represents a consolidated printer filament112 production method that combines a polymer in a liquid state with afiber 312 tow. A liquid state in this case will not be defined such thatthe definition would require a phase transition since amorphousthermoplastics considered do not undergo cold-crystallization in whichcase melting is ill-defined or must be assigned an imprecise value. Theexact embodiment of this process can vary. One method is to have a bathof molten polymer with the fiber 312 tow passing through the bath. Therollers over which the printer filament 112 passes may beneficiallyreduce the distance the polymer in the melt must travel to thoroughlywet all fiber filaments within the fiber 312 tow. When exiting thepolymer bath, the consolidated printer filament 112 can pass through aconstriction to remove excess polymer and to form a cylindrical crosssection so the printer filament 112 is ready to go to the printer.

A flattened cross-section can also be used for ease of winding since inany consolidated printer filament 112 manufacture process it could bebeneficial to wind the consolidated printer filament 112 and later feedthe printer filament 112 to the printer than having the consolidateprinter filament 112 fabricated as the printer is running. Anotherconfiguration that directly combines molten polymer with fiber tow 388is that of a modified extrusion process. In this method the fiber tow388 is pulled through a constriction while the molten polymer is addedcircumferentially with pressure. Any of these methods would result in aconsolidated printer filament 112 that has a uniform distribution offiber filaments within the polymer matrix 114. This last method isbeneficial in that achieving sufficient wetting to have this uniformdistribution with a consolidated printer filament of the diameter thatis desirable for the additive manufacturing machines described occursquickly enough at reasonable temperatures and pressure to allow muchfaster linear tow speeds than when using much larger or multiplecombined tows. This is beneficial in maintaining a sufficient throughputvolume for economic viability.

Referring next to FIG. 34, shown is a flowchart comprising labeled boxes600 and arrows 800, as well as words near arrows. The labels and wordsare specified in the structure.

The connections between the boxes 600 are shown to define a processflowchart and words next to arrows 800 specify the form of the materialat each stage. The first set of words are ‘carbon tow’ and ‘powderedpolymer’, which are inputs to a filament processor (heat, pressure,time, etc.) 1044. ‘Carbon tow’ can, more generally, be taken to mean‘fiber tow’. The output of the filament processor 1044 generates a‘composite three-dimensional printer filament 14’ or composite printerfilament that is input to the three-dimensional printing apparatus 1046(another term for additive manufacturing machine).

In operation, this is a process for filament production that can beimplemented in two methods. Both methods result in a fiber 312 tow thathas small polymer particles distributed throughout in the desirablevolume ratios as an intermediate step. After this step, heat andpressure are used to melt these particles, which, already being fairlyuniformly distributed, allow rapid consolidation of the filament intothe final form of uniformly distributed fiber filaments within a polymermatrix 114. In one method, particles are sprayed or adheredelectrostatically to the tow. During this coating process, the tow canbe passed over rollers 308, 310 that expose a greater number of the towfilaments to direct contact with the particles. The other methodinvolves having the polymer particles in a low-temperature fluid mediumor a solvent, in which case it may be incorrect to describe the polymermaterial as being particulate. The tow passes through this fluid andpolymer adheres to the tow. Subsequently, the fluid or solvent mediummight need to be removed to achieve optimal properties. The powdercoating that occurs in air or other gaseous environment is beneficial inthat there is no need to remove any residual solvent.

Referring next to FIG. 35, shown is a flowchart comprising labeled boxes6000 and arrows 800, as well as words near arrows. The labels and wordsare specified in the structure.

The connections between the boxes 600 are shown to define a processflowchart and words next to arrows specify the form of the material ateach stage. The first set of words are ‘carbon tow’ and ‘monomers oroligomers’, which each serve as inputs to a filament processor (heat,pressure, time, etc.; polymerization option) 1044. ‘Carbon tow’ can moregenerally be taken to mean ‘fiber tow’. The output of the filamentprocessor 1044 is a composite three-dimensional printer filament, whichserves as an input to the three-dimensional printing apparatus(polymerization in printing if incomplete) 1046 (another term foradditive manufacturing machine).

The final method suggested for fiber filaments 90, involves oligomersand/or monomers. The methods to utilize these materials instead ofpolymers is similar to the ones mentioned above and is a combination ofthe different elements from those methods. However, there are manybenefits from not beginning with a polymer. What is common among allthese processing methods is the application of heat and pressure forsome amount of time somewhere in the process. These are the physicalprocesses generally needed to effectively form the final consolidatedprinter filament 112. The heat and pressure must be sustained such thatall or most of the fiber filaments are effectively permeated withpolymer 114 and the limiting factor for this process can be the inherenthigh viscosity of thermoplastic polymers.

Oligomers and monomers on the other hand are beneficial since thosepre-polymeric materials can have orders of magnitudes lower viscosityand easily wet out the fiber filaments such that there is a uniform,albeit heterogeneous (since reinforced printer filament 14 andconsolidated printer filament 14 are composite materials), distributionlooking at the cross section. Once the fiber tow 388 has an evendistribution of oligomers and/or monomers with the correct weight ratio,heat and pressure may be applied to form the final consolidated printerfilament 114. The step with heat application sees the oligomers andmonomers polymerize, and the materials is then a polymer of similar oridentical characteristics to those typically used in non-reactiveprocessing methods. This can be beneficial in reducing the processingtime or resulting in a better final consolidated printer filament 14than is possible by any other method. Furthermore, this processingmethod could be the most beneficial for in-situ consolidated printerfilament formation where the step from unconsolidated printer filamentto consolidated printer filament 112 is directly integrated into theadditive manufacturing machine rather than spooling the material ontocreels and later unspooling the printer filament as the printer filamentfeeds into the printer.

Referring next to FIG. 36, shown are several polymeric molecules 360.Shown are molecular bonds 362. Shown are a pair of arrows 364 withlabels.

The arrow labels represent increasing or decreasing temperatures. Thesystem shown on the left and right are the same and the arrows indicatetransitioning from one state to another. Molecular bonds 362 in betweenthe polymer chains is only shown on the right. It should be noted thatthis diagram is not meant to be an accurate scientific representation ofa polymer system, rather it highlights one aspect of polymer systems forwhich this representation is not too abstract.

In operation, this shows a system that exhibits properties of boththermoset and thermoplastic polymers, which are typically considerednon-overlapping classes of materials. However, there is no inherentreason a hybrid system could not exist and such a system would have manybenefits. In a thermoplastic, the molecular structure maintains theappearance of the image on the left, where the polymers are heldtogether by intermolecular forces rather than covalent bonds. As thetemperature rises, the kinetic energy exceeds that of the intermolecularforces and these molecules begin to slide past each other in aliquid-like state. When the system cools, the polymer re-solidifies.Provided that the temperature reached is not excessive, this heatingcycle can be repeated many times with virtually no damage to thepolymers. On the other hand, thermosets undergo a permanent chemicalreaction where covalent bonds connect the polymer chains together. Afterthis reaction, the thermoset cannot be re-melted. Thermosets oftenexhibit beneficial properties such as higher hardness and strength.Furthermore, thermosets often have a very low viscosity before curing (3orders of magnitude lower than thermoplastics, typically).Thermoplastics have the benefit of reprocess ability, which isbeneficial when one might want one processing step that forms aconsolidated printer filament 14, and then a subsequent step of additivemanufacturing.

In operation, the system shown achieves the benefits of both thermosetsand thermoplastics. As the temperature decreases as indicated by thearrow pointing right, covalent bonds form between the polymer chains.However, as the temperature rises, as indicated by the leftward pointingarrow, the covalent bonds break allowing the polymer system to enter aliquid-like state instead of burning as would be the case with astandard thermoset. FIG. 37 through FIG. 41 show in more detail how sucha polymer system might be applied to additive manufacturing systems thatinclude reinforcement. The polymer chemistry is only one component,therefore aspects of applications of these reversibly-thermosettingpolymers are contemplated as they can be implemented in additivemanufacturing systems in a general sense are also described within thesefigures.

In additive manufacturing, printer filament 14 connect to each other toform a part. As described in FIG. 2, the segment of lament being addedfrom the nozzle 10 connects to the subset of the part that can be foundon the build plate 42, having already been fed from the nozzle 10. Themost recent segment of printer filament 14, as it exits the nozzle 10,is at a higher temperature than the solid ‘sub-part’ it connects to.When this segment of printer filament 14, which is typically in a moltenstate, contacts the sub-part, heat transfers from the most recently fedprinter filament 14 to the section of the sub-part with which it makescontact. In this contact area, the heat transfer is often sufficient tomelt the surface of the sub-part such that the recently fed printerfilament 14 bonds to the sub-part, which is the iterative process bywhich the part forms. However, as previously contemplated, this thermalbond is not as strong as those bonds within the bulk of the polymerwithin the printer filament 14. Having a sufficiently stronginter-printer-filament bond is of greater benefit for the higherperformance reinforced printer filaments and consolidated printerfilaments described herein because this inter-laminar bond can become alimiting factor that prevents attainment of the higher performanceproperties. For a printer filament 14 of a typical thermoplasticpolymer, a temperature hot enough for perfect bonding that is alsofeasible from a mechanical and thermal degradation perspective does notexist. This impossibility to achieve a perfect bond is due to the largesize of thermoplastic polymers and that the bonding process, known asreptation, requires the polymer chains to move and intertanglesubstantially. This has long been a problem facing additivemanufacturing, especially when reinforcing materials are used.

In contemplating the prior paragraph, lower viscosity is not the solebenefit of applying reversibly-thermosetting polymers to the additivemanufacturing systems described. Reversibly-thermosetting polymers, haveattributes of thermosets that include lower molecular weight and theirbonding process is different than that of thermoplastics. Instead ofneeding to reptate, or intertwine long chains as in a thermoplastic,reversibly-thermosetting polymers can form covalent bonds at theinterface that have comparable properties to the bulk of the polymer.This ‘complete bonding’ would occur when the printer filament 14contacts the sub-part. The kinetics are orders of magnitude apart. Thecomplete bonding of reversible-thermosetting based printer filament 14would beneficially allow more useful implementations of reinforcingmaterials in additive manufacturing. One of the properties thatquantifies this effect is interfacial shear strength, which is known tobe lower in thermoplastic composites that are additively manufacturedthan those thermoplastic composites produced by other methods such aspress forming.

Another problem posed by the high viscosity of thermoplastics is thatadditively manufactured parts comprising thermoplastic materials containvoids between the individual printer filament 14. As with imperfectbonding, voids are most detrimental when one wants to improveperformance with reinforcement because voids can create a limitingfactor. Reversibly-thermosetting polymer in printer filament 14 canbeneficially address this problem by more effectively filling thesevoids and lower the overall void percentage of the final part.

There are potentially several other benefits from usingreversibly-thermosetting polymers for the described applications.Thermoset parts are more effective than thermoplastic at preventingcreep, which is one of the major factors limiting their use in highperformance composites applications. Furthermore, reversibly-thermosetparts could be recycled with far more ease than thermoplasticsespecially if a discontinuous as opposed to continuous reinforcement isimplemented. For the same reason that reversibly-thermoset based partscould more easily be recycled, those parts could also be reformed intonew shapes more easily. Another benefit is that the fusion weldingreinforced or unreinforced additively manufactured parts comprising areversibly-thermosetting polymer would be more effective and easier toimplement than with thermoplastics. Fusion welding is essentially whatoccurs in additive manufacturing at a small scale so this would makesense. Fusion welding is beneficial since it removes the need forfasteners 74, which increases integrity and performance of the overallstructure. Furthermore, fusion welding is even more beneficial forcomposites since their properties decrease at attachment points due tojoints such as those involving holes or fasteners more so than metalalloys. It is also contemplated that all the aforementioned benefits canalso apply to injection molded parts comprising short reinforcements ina reversibly-thermosetting matrix material.

Referring next to FIG. 37 is a cross sectional view of a creel 314 offiber tow as well as a segment of the fiber tow, a container 382, afluid medium 370, and a plurality of rollers 380.

The segment of fiber tow is connected to the creel 314, and passes overeach roller 380. The container 382 holds the fluid medium 370, and inpassing over the rollers, the fiber tow segment passes through the fluidmedium 370.

In operation, the container 382 heats the fluid to an elevatedtemperature that is a compromise between optimizing fluidity and polymerdegradation since the fluid is a polymer bath. The fiber tow can be acarbon fiber tow, and for this process multiple creels can be combinedsuch that there are more total fiber tows in each bundle. A single fibertow of a lower fiber filament count is more likely to be implementedwhen the subsequent consolidated printer filament 112 is to be useddirectly in an additive manufacturing machine. Some of the benefits ofconsolidated printer filament 112 as opposed to reinforced printerfilament 398 have been stated, but this polymer also allows an increasein beneficial applications that utilize short reinforcement 90. Largertows or multiple tows are more likely to be used if the output of thisprocess is used to make a reinforced printer filament 398 that utilizesa polymer of the type described in FIG. 36.

This seems similar to an implementation of that which was suggested inFIG. 33, however it is different in that this process is animplementation that uses the polymer described in FIG. 36. Using thispolymer has several benefits. The lower viscosity is beneficial inallowing the fiber filaments to be wet out more easily by the polymer.This means the process can be improved. It is also possible to lower thetension in pulling the fiber filaments over rollers since less towspreading might be needed for the polymer to fully permeate the tow.This is beneficial in reducing the probability of fiber filament damage.Furthermore, it might be easier to reach the temperature to enable fullywetting the tow without a risk of heat degradation of the polymer.Another benefit is that since wetting out would occur much more rapidly,the entire process can be accelerated to achieve higher throughput.

Referring next to FIG. 38, a schematic view is shown including a lastpart of the fiber tow segment from FIG. 37. Since this fiber tow is thatof FIG. 37, which has been wet out with polymer 114, it is technically aconsolidated printer filament 112, although for this method the printerfilament 112 might be of a larger diameter than would desirable were theprinter filament 112 to be used directly in an additive manufacturingmachine. Shown is a roller 380. Shown is a cutting blade 384. Shown area plurality of short pieces 389 of the consolidated printer filament112. Shown is a container 382.

The end of the consolidated printer filament 112 is passing over theroller 380. The cutting blade 384 is near the end of the consolidatedfiber filament. The chopped pieces 389 are in front of the cutting bladeand most of them are within the container 382.

In operation, this represents an addition to the process from the priorimage where instead of spooling continuous fibers onto creel 316, thefiber is cut into short pieces 389 that might be collected in acontainer 382. This is a method by which one would obtain a reinforcedprinter filament 112 instead of a consolidated printer filament 398.Reinforced printer filament 398 are beneficial since those printerfilaments can be used with additive manufacturing machines that havenozzle 10 ends with a diameter smaller than the diameter of the printerfilament. The length of these pieces (or pellets) can be varieddepending on ideal processing parameters. Their diameter is determinedin the method of FIG. 37 which can be estimated four factors: totalfilaments in all tows that get brought together (can be as few as one),overall fiber volume percent, and the densities of the constituentmaterials. These pellets contain reinforcements that are discontinuousfibers as implied by FIG. 37 involving fiber tows, and it is feasible tohave the discontinuous fiber be several times longer than the criticallength, which has the benefit of maintaining most of the mechanicalproperties that continuous properties exhibit. Pellets of the polymer ofFIG. 36 produced by methods other than that of FIG. 37 that compriseother reinforcement can also be beneficial for FIG. 39 and FIG. 40,which follow.

Referring next to FIG. 39, a cross-sectional schematic view is shownincluding a constant diameter screw extrusion machine 390, pellets 392,a hopper 394, a screw 396, short reinforcements 90, reinforced printerfilament 398, a reel 314, and an outer piece of the extrusion machine.

Some of the short reinforcements 90 are in the pellets 392, others aresuspended within the fluid in the extrusion machine 390, and others arein the reinforced printer filament 398. The outer part of the extrusionmachine 390 surrounds the fluid and has a screw 396 in the middle. Thehopper 394 is positioned on one end of the apparatus and contains thepellets 392. The other end of the apparatus has the reinforced printerfilament 398 and the creel 314. In between, the pellets 392 become themelt pool containing short reinforcements within the extrusion machine.

The general process by which one would make a reinforced printerfilament 398 is shown. This process is a representation and variousother components either can optionally be included such as heater bands,a cooling bath, sensors, controllers, winders, etc. The hopper allowspellets to fall into the screw mechanism as space becomes availablebetween threads. The pellets can be produced with a process of the typedescribed in FIG. 35. The screw tapers as shown. This taper crushes thepellets against the inner walls of the extrusion machine. If the screwdoesn't taper, the flutes/threads of the screw can provide sufficientpressure to crush the pellets. The screw is rotated to feed the pelletsalong a pipe. The end of this pipe has a hole that can vary in diameter.This hole is designed to produce the shape of a filament or object.Extrusion machines operate such that this crushing of pellets thatcreates viscous shear forces causes the majority of melting, and anyheater bands contribute a much smaller amount of heat. This has manybenefits for the ease of injection molding and reinforced printerfilament 398 production.

However, the introduction of reinforcement in injection molding andprinter filament production is often less effective than desired. Theseviscous shear forces that melt the pellets through crushing are highlydeleterious to the short reinforcement and are known to cause lengthattrition when the reinforcements are fibers. The average fiber lengthcoming out can be an order of magnitude lower than that going in. Theshorter fibers results in significantly worse material properties thanwould be attained were the length of the fibers to be preserved.However, since it is the viscous shear that induces fiber damage, lowerviscosity is highly beneficial. Therefore, by using the pellets of FIG.37, that utilize the polymer of FIG. 36, it is possible to both producereinforced printer filament 14 for additive manufacturing as well asinjection mold parts, with fiber reinforcement where there is asubstantially less fiber length attrition, due to the far lower viscousshear force required in processing. This means injection molded andthree dimensional printed parts can be made with strength, stiffness,and other properties, several times better than the state of the art.Furthermore, if there were any other polymer with a sufficiently lowviscosity, it could also be used in this process.

Referring next to FIG. 40, shown is a cross-sectional schematic view ofa pressure-based extruder 400. Shown are pellets 392, numbers ‘1’ and‘2,’ a pressure-based extruder, short reinforcements 90, a melt pool, areinforced printer filament 298 and a creel 314.

The numbers are shown adjacent to the apparatus at times ‘1’ and ‘2’. Inthe top image, pellets 392 are within the pressure-based extruder andthe majority of the pellets 392 are still within a pressure-containingvolume. In the lower image, the pressure has caused the shortreinforcements shown to form a profile in front of the pressure chamber.This pressure can be applied using a piston, bladder, viscous fluid, orany method of applying pressure that causes the pellet-derived-melt-towto tow from the tip of the extruder. Reinforced printer filament 398extends outward from the end of the extruder, and is shown spooled ontoa reel 314.

In operation, the pressure-based extruder extrudes reinforced printerfilament 398 for additive manufacturing. This style of process can beused similarly to that of FIG. 39. This process has the benefit of notusing a screw mechanism. In this system a greater amount of heat can bedelivered through conduction. Microwave or other forms of radiation arealso contemplated in accordance with other embodiments. Thepressure-based extruder is not as effective as screw-extruders forinjection molding with typical thermoplastics, which is why thepiston-extruder is not typically used, but since reinforced printerfilament 398 production requires pushing material through at a volume180 four orders of magnitude slower than in injection molding, it makessense to consider the benefits of producing reinforced printer filament398 with a piston style extruder if fibers are being used for the shortreinforcement. If a low melt-viscosity polymer such as that of FIG. 36is used, it is possible to obtain reinforced printer filament 398 witheven less fiber length attrition than by the process described in FIG.39. If this process is used with an ordinary high melt-viscositythermoplastic, it is possible to also prevent a large amount of thefiber length attrition associated with the screw process. It isbeneficial to be able to use thermoplastic polymers with a lowerviscosity. Typically, in polymer science, any polymer composition is acompromise among various properties and thus each engineeringapplication may require a unique composition. It is also contemplatedthat embodiments of the piston based extruder, rather than producingfilament for printing, could be directly integrated into a large-formatadditive manufacturing machine where it would operate as a nozzle, whichbeneficially allows for increased material deposition rates and a moreintegrated overall system.

Referring next to FIG. 41, a perspective view is shown of a matrix block410, and reinforcement fibers 90 that can also be whiskers 412 orreinforcement materials of other morphologies. Reinforcement fibers 90are contemplated in their general sense as described in FIG. 9.

The reinforcement fibers 90 are distributed throughout the matrix of thefiber matrix block 410.

The fiber matrix block 410 represents a fiber matrix composite producedby additive manufacturing, but the fiber matrix block 410 isfundamentally different from the fiber reinforced polymer compositepreviously described in FIG. 18. The fiber matrix block 410 is not apolymer matrix composite, but a ceramic matrix composite. Ceramics arebeneficial in withstanding extremely high temperature and pressure whileretaining hardness and other properties, which makes ceramics among themost refractory materials. Their refractoriness is many times higherthan metallic alloys and even more times higher than polymers, whichhave low refractoriness. Composites with a variety of matrix materialsare often beneficial in engineered systems, and it is beneficial toutilize both ceramic matrix composites and polymer matrix 114 compositesin similar additive manufacturing platforms. It is possible tothree-dimensionally print ceramics by mixing a ceramic powder into apolymer and then baking the final structure, but this results inporosity, which limits the applications. Porous ceramics have poormechanical properties including strength and damage tolerance. Fullydense ceramics are beneficial for engineering application, whereasporous ceramics are not suitable for much more than dinner plates.

FIG. 35 points out how one could additively manufacture with monomers oroligomers instead of polymers. Monomers could contain the primaryelements or molecules that are precursors to ceramics. These wouldbecome pre-ceramics polymers prior to becoming ceramics. One would printthis material into a complex structure. That structure could be baked ata high temperature, which would remove the functional groups and leave ahigh-performance ceramic that is virtually free of porosity.

However, to truly capture the benefits of ceramics, one can utilizevarious aspects of fiber reinforcement described herein. While one mightutilize different fiber materials and other fiber forms such as whiskers412, the principles are the same. Being able to three-dimensional printhigh performance ceramic matrix composites is highly beneficial and is agood complement to polymer matrix 114 composites within complexmulti-material systems. If one generalizes this concept further, itshows that the principles of substituting novel constituent materialsinto the processes described herein can apply to virtually any materialsthat can be three dimensional printed in a similar fashion to fuseddeposition modeling. As new materials are developed, whether matrix orreinforcement, the systems and methods described herein provide astraightforward path by which the additive manufacturing systems canbeneficially move from lab to industrial scale manufacturing through auniversal and highly adaptable processing system. It is contemplatedthat the use of multiple materials could be extended to a more generalautomated manufacturing process that includes components such as sensorsthat could even be built directly out of the constituent materials.

Another embodiment to produce ceramic matrix composites would be with aUV-curing pre-ceramic oligomeric, monomeric, or polymeric baththree-dimensional printer with the addition of short reinforcements thatcan be suspended in the bath. It is contemplated that such a ceramiccomposites additive manufacturing machine would not function for allembodiments of UV-curing-based three-dimensional printing methods knownin the art since the short reinforcement could block the UV radiation,preventing polymerization of the polymer in its ‘shadow’, particularlyif a self-propagating waveguide is used instead of polymerizing only thelayer of the bath near the surface as the upside-down platform movesupward.

Referring next to FIG. 42, a flowchart is shown having a plurality ofboxes connected by arrows.

The boxes each contain a set of operations and the arrow connectorsindicate the ordering of these sets of operations.

In operation, this figure demonstrates the overall set of processes thatcan be used to convert a polymer matrix composite into a ceramic matrixcomposite. It is particularly beneficial for carbon fiber reinforcedthermoplastic parts, including those that are three dimensional printedwith the methods described herein.

Ceramic matrix composites operate differently from polymer matrixcomposites at a fundamental micromechanical level. In polymer matrixcomposites, loads are transferred from the weak and ductile matrixmaterial to the strong, stiff, and brittle fibers, and these loads aretransferred at the fiber matrix interface through shear stresses.Therefore, polymer matrix composites benefit from a strong interfacialshear strength. Ceramic matrix composites have a matrix that is alsostrong, stiff, and brittle. The ceramic matrix of a ceramic matrixcomposite can take a useful load and the fibers serve the differentpurpose of bridging cracks, which would otherwise cause the material tofail at much lower loads. Therefore, it is beneficial for the ceramicmatrix composite to have a weak fiber matrix interface that allows thematrix to slip from the fiber. This prevents the material from becominga monolithic ceramic. This necessitates a coating for treatment to thecarbon fiber prior to it being formed into a printer filament. Coatingand fiber treatment methods are disclosed in detail in FIG. 43.

The following step of forming a suitable printer filament can beaccomplished with the same methods as those described in other figures.The only notable difference is that when the coating is thick enoughthat the bend radius is significantly reduced, printer filaments withthe reinforcements being discontinuous can be beneficial since it allowssharp angles in the movement of the printer head during athree-dimensional printing operation without breaking or otherwisedamaging the printer filament as could occur with a higher bendingradius continuous reinforced printer filament.

Once the printer filament is produced, a polymer composite part isformed by any of the three-dimensional printing methods describedherein.

Pyrolization can be used to convert a polymer matrix composite into acarbon ceramic matrix composite. Pyrolization involves heating thepolymer matrix composite, and pyrolization occurs at a highertemperature than the glass transition temperature and higher than themelting temperature. With a thermoset-based polymer matrix compositethis is not a problem since melting does not occur due to thecrosslinked molecular structure. Therefore, it can be beneficial toinclude another step prior to pyrolization in which a non-thermoplasticcoating is applied to the thermoplastic part to prevent part deformationfrom melting during pyrolization. This coating process and thesubsequent pyrolization is disclosed in detail in FIG. 44.

After pyrolization, the resultant material is a carbon carbon ceramicmatrix composite. Following this, the carbon carbon composite can beused as is, which may involve several subsequent processes that can bebeneficial depending on the application. Some of these processes mightrequire novel modifications due to the variations between typical carboncomposites and those produced with the methods described herein.Alternatively, it might often be beneficial to carry out liquid metalinfiltration on these carbon carbon parts, which requires multiple novelelements as disclosed in FIG. 45, due to the novel method that is usedto form the initial carbon carbon composite.

Aside from minor operations such as machining in between certain steps,this process outlines an entirely novel and complete manufacturingprocess to obtain ceramic matrix composite parts and structures. Thecombination of all these processing methods poses numerous benefits withconsideration both to the performance and properties of individualparts, and to the viability of complex systems and assemblies thathitherto have not been realizable due to economic or engineeringfactors.

Considering the attainable properties at the part level, many of thebenefits are similar to those disclosed for polymer composite parts.Currently, ceramic composite parts have the same limitations in fiberorientations as polymer composites, but this system enables a vastdesign space with consideration for fiber orientation. Furthermore,whereas moderate geometric complexity is possible in polymer composites,ceramic composites have even more manufacturing limitations resulting ineven lower levels of geometric complexity. This process enables an evenlarger jump in complexity in ceramic composites than that of polymercomposites. Due to the aforementioned micromechanical slip-model withcrack bridging/arresting in ceramic matrix composites, the ability totailor fiber orientations to particular applications could be even morebeneficial than in polymer composites. In addition to improvedproperties related to load-bearing such as strength and toughness,tailored fiber orientation could be implemented to produce parts withnear-zero coefficients of thermal expansion at a macro-scale. Very lowthermal expansion is beneficial in applications such as satellitecomponents where Invar is currently used. Ceramic composite partsprovide the benefit of reduced weight and possibly even lower thermalstability, as well as lower cost. Tailored fiber orientations fortoughness can offer one of the largest benefits in ballistic armorapplications. Jet engine components could have their weight reduced byswitching from super alloys to these components, as could thermalprotection systems for hypersonic vehicles, including UAVs and missiles.In both applications, it is beneficial to be able to produce highlycomplex shapes. Furthermore, this three-dimensional printing process isbeneficial by allowing a large number of design iterations due to theabsence of the cost for a machined mold. This is particularly usefulwhen implemented in conjunction with the computational methods describedherein for part optimization.

Referring next to FIG. 43, shown is a side cross-sectional view showinga coating on the carbon filaments prior to consolidating into acontinuous filament for the printer. Shown is a fiber tow 420 a and anoven 422; shown is a fiber tow 420 b and a flame 424; shown is a fibertow 420 c, rollers 308, 310, and a bath 370; arrows are shown.

The fiber tow is shown to pass through the oven; the fiber tow is shownto pass over a flame; the fiber tow runs over the upper lowers and underthe lower rollers, allowing it to pass through the liquid in the bath.The fiber tows are bundles of carbon fiber filaments without a matrixmaterial. These could be 1K, 3K, 6K, 12K tows, or some other tow size.

In operation, the fiber tow is passed through an oven; the fiber tow ispassed over a flame; rollers are used to pass the fiber tow through aliquid bath. These three operations, independently or in somecombination, allow for a large number of methods to apply a coating ortreatment to the carbon fiber, but it is not exhaustive.

The liquid bath is a common method for applying a coating that iscommonly known as a sizing. A phenolic sizing could form a layer ofpyrolytic carbon on the carbon fibers to protect them during liquidmetal infiltration. For instance, when silicon is the metal being used,this beneficially prevents the silicon from attacking the carbon fiberitself and keeps the ceramic part from becoming monolithic. If a polymersizing with a higher percent char residue such as polyarylacetylene isused, there can be an even greater benefit due to a denser layer ofprotective pyrolytic carbon. Other polymer coatings could be pre-ceramicto obtain interphases at the fiber matrix interface other than pyrolyticcarbon. Boron nitride, silicon nitride, and silicon carbide are some ofthe beneficial coatings that could be obtained during pyrolization withpre-ceramic coatings. A polycarbosilane coating would be a good optionfor converting the carbon fibers to silicon carbide fibers duringpyrolization. The particular coating used is beneficially selected basedupon the final application since oxidative damage to some ceramicmaterials can reduce the maximum use temperature.

Coatings or treatments that are not polymeric or pre-ceramic can benefitfrom methods other than the liquid bath sizing. The step with a flamecan be thought of to represent a wide variety of coating methods thatcan involve physical deposition, chemical deposition that can bereactive, or a purely reactive process such as oxidation. Theseprocesses can occur in air, a vacuum, or inert atmospheres such asnitrogen or argon. For instance, Chemical Vapor Reaction, or CVR, is amethod of converting carbon fibers into silicon carbide fibers, whichhave a silicon carbide coating. CVR is beneficial since it can producefar thinner coatings than those in typical silicon carbide fibers, whichallows a lower bend radius, enabling three-dimensional printing ofdiscontinuous or continuous fibers. Other coatings such as boron nitridecan also be applied in this process. Part of this figure shows an oven,which can be used in conjunction with the other steps in this figure,but it is meant to emphasis the heat treatment aspect. Heating the fibercan alter the surface, and depending on the atmosphere, this can removefunctional groups on the fiber surface. This has the benefit ofdecreasing interlaminar shear strength in the polymer composites, whichcan be used instead of an additional fiber coating to reduceinterlaminar shear strength in the ceramic composite, although it canalso be used as a step that precedes adding a coating to the fiber.

Referring next to FIG. 44, a schematic diagram is shown showing acoating 428 applied to a printed polymer composite part 424, and fillinghollow portions with foam, prior to pyrolization as an option tomitigate part deformation and subsequent removal. Shown is a container382, a liquid 370, a part 424, and a coating 426 is shown; a honeycombstructure 428, along with foam 430 and an injection nozzle 432 is shown;a part 424 and a coating 426 is shown, and a part 424 without a coatingis shown.

The liquid is held in the containers, and the part is initiallysubmerged in the liquid container. Subsequently, the part is shown witha residual coating above the surface of the liquid. Then a honeycomb isshown, which has non-closed cells, each containing foam, originatingfrom the injection nozzle. Then a coated part is shown followed by anuncoated part.

FIG. 44 shows a system for performing the method described in referenceto FIG. 42 to prevent part deformation during pyrolization. The initialcoating application is one possible method for applying a thermosetcoating to the part, which might then require thermal crosslinking.Thermal crosslinking could be a separate step preceding pyrolization, orit could be possible to have the thermoset cure during the pyrolizationprocess. Reactive crosslinking that occurs at standard conditions isalso an option. The coating could be a material other than a typicalthermosetting polymer. If a refractory material such as a ceramic caninstead be applied, it will provide even greater rigidity to preventdeformation during pyrolization, and since the refractory material doesnot pyrolize along with the polymer matrix material it is easier toremove in the final step where the coating is removed afterpyrolization. However, a thermoset polymer coating is beneficial whenits contraction during pyrolization can be made to match the contractionof the internal composite part. If the shrinkage rate of the thermosetcoating is made to match the composite part during the initial stages ofpyrolization, but then decrease could optimally allow for structuralsupport while the thermoplastic is still malleable, but then separate toallow easy removal.

In three-dimensional printing, it is often beneficial to produce hollowinternal structures to reduce weight. These sorts of structures are notpresent in existing ceramic composite parts. There is a risk that duringpyrolization the internal structure could collapse or cause deformation.Therefore, it can be beneficial to introduce a lightweight internalsupport structure. Various foams could be introduced into the structure,which would pyrolize at low temperatures, thus forming a low-densitysupport structure. Once any coatings or foams are applied the part ispyrolized, after which the coating can be broken or machined of, ifdesired.

Referring next to FIG. 45, a schematic diagram is shown showinginfiltration of pyrolized part with silicon and joining. Shown is a part424, a container 382, and a liquid 370. Shown is an additional part 425.

The first diagram in a sequence shows liquid in a container with thepart above the liquid. Two different steps can follow this one. Eitherthe part is submerged into the liquid or it is submerged into the liquidtogether with a second part. Finally, the part or joined parts that forma single part are removed from the liquid.

In operation, this is the liquid metal infiltration step described inreference to FIG. 42. Silicon is the preferred metal for this step andit converts the matrix material from carbon into silicon carbide,forming a dense ceramic matrix. It is worth noting that thethree-dimensional printing processes disclosed throughout, by leavingvoids between the printed filaments, can result in micro-channels thatfill with silicon. These channels of silicon could be highlybeneficial—during operation of the part at elevated temperatures thatexceed the melting temperature of silicon, the silicon channels would beable to flow, and this flowability would be present throughout the part.The reflow of the silicon could allow cracks to be filled as well asreactive bonding depending on the surfaces encountered by the silicon.This effectively allows the part to self-heal when heated to thesetemperature, which is highly beneficial for the survivability anddurability of the part and structure since ceramic composites absorbenergy through micro-cracking that overtime worsens the partsproperties.

The infiltration process to produce the silicon carbide matrix ceramicis executed by dipping the carbon carbon part into a bath of liquidsilicon. Since this is a reactive process it is possible to form largeror more complex parts by melt-infiltrating parts positioned next to eachother. It is also possible to join parts after this process by reactiveor non-reactive melt joining.

Furthermore, it is beneficial if the joining process involves othermaterials such as molybdenum disulphide that provide a superior barrierto high temperature oxidation when the carbon fibers are not siliconcarbide fibers. Combining such a coating with the continuous carbonthree-dimensional printing process is beneficial in that there are fewerfiber ends per fiber length as compared to parts formed from woven fibermats. This reduces the area that can suffer oxidation at elevatedtemperatures. The three-dimensional printing process further benefitsthe infiltration process since the voids that run parallel along all theprinter filaments allow a path for the infiltrating metal to enter intomore complex or thicker structures. Silicon effectively wicks throughcarbon carbon composite parts, but once the silicon reacts with thepyrolized carbon matrix, it forms a dense ceramic impeding the furtherflow of silicon, and the micro-channels can effectively overcome thisimpediment.

While the invention herein disclosed has been described by means ofspecific embodiments, examples and applications thereof, numerousmodifications and variations could be made thereto by those skilled inthe art without departing from the scope of the invention set forth inthe claims.

What is claimed is:
 1. A method of additive manufacturing comprising:moving a nozzle relative to a workpiece on a build plate, in fivedimensions comprising: moving the nozzle in three dimensions defined byan x-axis, a y-axis, and a z-axis; rotating the nozzle in a first planeby rotating the nozzle about a pivotal joint; and rotating the buildplate about a center point of the build plate in a second plane notparallel to the first plane; feeding a printer filament through thenozzle; heating the printer filament with a radiant heat source as it isfed through a central filament guide tube of the nozzle, the nozzlefurther comprising a radiative chamber encircling a segment of thefilament guide tube, wherein at least one interior surface of theradiative chamber is reflective of radiant heat from the radiant heatsource; and depositing the heated printer filament from the nozzle ontothe workpiece, wherein the nozzle and the pivotal joint are configuredto enable the nozzle to rotate about the pivotal joint without yankingthe printer filament and without allowing excessive slack in the printerfilament while the nozzle is being rotated.
 2. The method of claim 1further comprising: forming the printer filament by processing a carbontow and a monomer by heating.
 3. The method of claim 1 furthercomprising: forming the printer filament by processing a carbon tow anda monomer with pressure.
 4. The method of claim 1 further comprising:forming the printer filament by processing a carbon tow and an oligomerwith heating.
 5. The method of claim 1 further comprising: forming theprinter filament by processing a carbon tow and a liquid phase polymerwith heating.
 6. The method of claim 1 further comprising: forming theprinter filament by processing a carbon tow and a liquid phase polymerwith pressure.
 7. The method of claim 1 further comprising: forming theprinter filament by processing a carbon tow and polymer tow bundledfilaments.
 8. The method of claim 7 further comprising: forming theprinter filament wherein said processing further comprises air jetcommingling.
 9. The method of claim 1 further comprising: depositing theprinter filament forms a three-dimensional part.
 10. A method ofadditive manufacturing comprising: moving a nozzle a first time relativeto a build plate using a five axis system, wherein the five axis systemcomprises the nozzle configured to move in three dimensions defined byan x-axis, a y-axis, and a z-axis, the nozzle configured to rotate in afirst plane by rotating the nozzle about a pivotal joint, and the buildplate configured to rotate about a center point of the build plate in asecond plane not parallel to the first plane; feeding a printer filamentthrough the nozzle; heating the printer filament with a radiant heatsource as it is fed through a central filament guide tube of the nozzle,the nozzle further comprising a radiative chamber encircling a segmentof the filament guide tube, wherein at least one interior surface of theradiative chamber is reflective of radiant heat from the radiant heatsource; depositing a first amount of heated printer filament onto thebuild plate, wherein the printer filament comprises a matrix and areinforcement, and wherein the nozzle and the pivotal joint areconfigured to enable the nozzle to rotate about the pivotal joint whiledepositing without yanking the printer filament and without allowingexcessive slack in the printer filament while the nozzle is beingrotated; moving the nozzle a second time relative to the build plateusing the five axis system; depositing a second amount of the heatedprinter filament onto the build plate, wherein the printer filamentcomprises the matrix and the reinforcement, wherein the second amount ofthe printer filament is connected to the first amount of the printerfilament, and wherein the reinforcement extends from the first amount ofthe printer filament into the second amount of the printer filament. 11.The method of claim 10 further comprising: moving the nozzle a thirdtime relative to the build plate using the five axis system.
 12. Themethod of claim 11 further comprising: depositing a third amount of theheated printer filament not on the build plate, wherein the printerfilament comprises the matrix and the reinforcement, wherein the thirdamount of the printer filament is connected to the second amount of theprinter filament, and wherein the reinforcement extends from the firstamount of the printer filament through the second amount of the printerfilament into the third amount of the printer filament.
 13. The methodof claim 10 further comprising: heating the build plate during thedepositing of the first amount and the second amount.